Can AI Answer My Questions? Utilizing Artificial Intelligence in the Perioperative Assessment for Abdominoplasty Patients.

BACKGROUND: Abdominoplasty is a common operation, used for a range of cosmetic and functional issues, often in the context of divarication of recti, significant weight loss, and after pregnancy. Despite this, patient-surgeon communication gaps can hinder informed decision-making. The integration of large language models (LLMs) in healthcare offers potential for enhancing patient information. This study evaluated the feasibility of using LLMs for answering perioperative queries. METHODS: This study assessed the efficacy of four leading LLMs-OpenAI's ChatGPT-3.5, Anthropic's Claude, Google's Gemini, and Bing's CoPilot-using fifteen unique prompts. All outputs were evaluated using the Flesch-Kincaid, Flesch Reading Ease score, and Coleman-Liau index for readability assessment. The DISCERN score and a Likert scale were utilized to evaluate quality. Scores were assigned by two plastic surgical residents and then reviewed and discussed until a consensus was reached by five plastic surgeon specialists. RESULTS: ChatGPT-3.5 required the highest level for comprehension, followed by Gemini, Claude, then CoPilot. Claude provided the most appropriate and actionable advice. In terms of patient-friendliness, CoPilot outperformed the rest, enhancing engagement and information comprehensiveness. ChatGPT-3.5 and Gemini offered adequate, though unremarkable, advice, employing more professional language. CoPilot uniquely included visual aids and was the only model to use hyperlinks, although they were not very helpful and acceptable, and it faced limitations in responding to certain queries. CONCLUSION: ChatGPT-3.5, Gemini, Claude, and Bing's CoPilot showcased differences in readability and reliability. LLMs offer unique advantages for patient care but require careful selection. Future research should integrate LLM strengths and address weaknesses for optimal patient education. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The Preservation of Umbilical Blood Supply in Combined Ventral Hernia Repair and Abdominoplasty: A Narrative Review.

INTRODUCTION: Combined ventral hernia repair and abdominoplasty treat risk factors such as high body mass index and weak abdominal musculature, providing excellent intraoperative exposure and improved patient outcomes. Unfortunately, a combination of traditional procedures is unfeasible as the umbilical blood supply would be compromised, leading to increased umbilical necrosis risk. This narrative review aimed to identify new techniques and solidify evidence in preserving umbilical blood supply and associated level of evidence. METHODS: Two authors conducted a thorough literature search on PubMed, Scopus and Cochrane CENTRAL databases from January 1901 to July 2023, adhering to the methodologies of the preferred reporting items for systematic reviews and meta-analyses. Studies were reviewed for their surgical technique and quality of evidence. The primary outcomes of interest consisted of umbilical complications of this combined procedure. RESULTS: Six techniques were identified that included laparoscopic, pre-rectus, unilateral, distal bilateral, proximal bilateral, and inferior midline approaches. All techniques demonstrated as viable options in preserving umbilical blood supply as reported complications were few, minor, and compounded by risk factors. However, all included techniques were limited to low-to-moderate-quality evidence. CONCLUSION: Despite the lack of high-quality evidence, all techniques remain viable options for combined ventral hernia repair and abdominoplasty. Large-scale high-quality RCTs are required to compare the effectiveness of various approaches with additional outcomes of hernia recurrence rates, intraoperative time, and patient- and surgeon-reported satisfaction. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Pre-rehabilitation interventions for patients with head and neck cancers: A systematic review and meta-analysis.

OBJECTIVE: To investigate the effect of pre-rehabilitation interventions such as nutrition and exercise for patients with head and neck cancer (HNC). METHODS: Web of Science, PubMed, Scopus, Google Scholar, and Cochrane databases were searched up to December 2022. Quality of life, length of hospital stay, postoperative complications, change in body mass index or muscle mass, and functional assessments were the primary outcomes. PRISMA guidelines were adhered to, and the study was registered on PROSPERO. The Cochrane Collaboration tool and Newcastle Ottawa scale assessed the quality of included studies. Pooled data are presented as odds ratios (OR) and 95% confidence intervals (CI). Analysis was conducted using RevMan5.4. RESULTS: A total of 31 articles were included for quantitative analysis and 15 for qualitative synthesis. Nutrition alone resulted in significant weight retention (2.60; 2.32, 2.88, p < 0.00001), length of stay (-4.00; -6.87, -1.13), p = 0.0006) and complications (0.64; 0.49, 0.83, p = 0.0009). Nutrition and psychoeducation resulted in a significant reduction in mortality rate (0.70; 0.49, 1.00, p = 0.05 and 0.60; 0.48, 0.74, p < 0.00001), and exercise resulted in a significant reduction in dysphagia (0.55; 0.35, 0.87, p = 0.01). Exercise with nutrition resulted in significant improvements in weight loss, length of stay, complications, and dysphagia. Randomized controlled trials (RCTs) had a moderate risk of bias and cohort studies were of fair to good quality. CONCLUSION: Prehabilitation programs based on exercise, nutrition, or psychoeducation demonstrated improved post-interventional outcomes in HNC, such as quality of life, and mortality and morbidity. Studies with longer follow-ups and larger sample sizes, and investigations comparing nutritional supplements with exercise programs are needed.

Improving Visualization of Intramuscular Perforator Course: Augmented Reality Headsets for DIEP Flap Breast Reconstruction.

Background: Augmented reality (AR) technology, exemplified by devices such as the Microsoft HoloLens 2, has gained interest for its potential applications in preoperative guidance. This study explores the use of AR technology for perforator identification during deep inferior epigastric artery perforator (DIEP) flap breast reconstruction. Methods: A case series of five patients where an AR device was used to identify perforators during DIEP flap breast reconstruction is presented. The device was utilized to recognize preoperative perforators and map their extra- and intramuscular routes. Sound and/or color Doppler confirmation was used to verify the findings. Results: In all five cases, the AR device successfully identified preoperative perforators and delineated their extra- and intramuscular routes. AR technology in perioperative visualization of vasculature offers the potential to enhance surgical precision and reduce operative times. By providing an augmented three-dimensional overlay of patients' vascular structures, AR can facilitate a more comprehensive understanding of individual anatomy, ultimately improving surgical outcomes. Conclusions: AR technology shows promise in enhancing perforator identification efficiency and deepening understanding of perforator trajectories during preoperative planning. Nonetheless, additional research is needed to establish whether the advantages of AR technology warrant its widespread adoption for perforator identification.

Use of Artificial Intelligence in the Advancement of Breast Surgery and Implications for Breast Reconstruction: A Narrative Review.

BACKGROUND: Breast reconstruction is a pivotal part of the recuperation process following a mastectomy and aims to restore both the physical aesthetic and emotional well-being of breast cancer survivors. In recent years, artificial intelligence (AI) has emerged as a revolutionary technology across numerous medical disciplines. This narrative review of the current literature and evidence analysis explores the role of AI in the domain of breast reconstruction, outlining its potential to refine surgical procedures, enhance outcomes, and streamline decision making. METHODS: A systematic search on Medline (via PubMed), Cochrane Library, Web of Science, Google Scholar, Clinical Trials, and Embase databases from January 1901 to June 2023 was conducted. RESULTS: By meticulously evaluating a selection of recent studies and engaging with inherent challenges and prospective trajectories, this review spotlights the promising role AI plays in advancing the techniques of breast reconstruction. However, issues concerning data quality, privacy, and ethical considerations pose hurdles to the seamless integration of AI in the medical field. CONCLUSION: The future research agenda comprises dataset standardization, AI algorithm refinement, and the implementation of prospective clinical trials and fosters cross-disciplinary partnerships. The fusion of AI with other emergent technologies like augmented reality and 3D printing could further propel progress in breast surgery.

The combined effect and mechanism of antiangiogenic drugs and PD-L1 inhibitor on cell apoptosis in triple negative breast cancer.

Background: Breast cancer is the most common cancer worldwide, and triple-negative breast cancer (TNBC) has the worst prognosis. Standard systemic treatment includes chemotherapy and immunotherapy. Poly ADP-ribose polymerase (PARP) inhibitors are considered in breast cancer (BRCA) susceptibility genes mutated tumors. The role of antiangiogenic drugs is controversial. Immunotherapy with immune checkpoint inhibitor is now a standard of care for TNBC in the US, but its use in combination with anlotinib, an inhibitor of angiogenesis, on TNBC cells was never investigated. Methods: We tested the effects of anlotinib and programmed cell death-ligand 1 (PD-L1) inhibitor on the proliferation, apoptosis, migration, and invasion of MDA-MB-468 and BT-549 TNBC cells through 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT) assays, cell apoptosis assay, wound healing and transwell matrix assays, and verified whether the combination of the two drugs had synergistic effect. Western blotting was used to detect the effect of anlotinib and PD-L1 inhibitor on the protein expression levels of PI3K, p-PI3K, AKT, p-AKT, Bcl-xl in MDA-MB-468 and BT-549 cells. The effects of anlotinib, PD-L1 inhibitor and the combination of the two drugs on the transplanted tumor of TNBC mice were tested by animal experiments. Results: Anlotinib and PD-L1 inhibitor inhibited the proliferation and promote cell apoptosis of MDA-MB-468 and BT-549 cells, and the combination demonstrated the synergetic effect. Anlotinib and PD-L1 inhibitor inhibited cell migration and invasion, and the effect was strongest in the combination group. Both anlotinib and PD-L1 inhibitor reduced the expression of p-PI3K, p-AKT and Bcl-xl proteins in cells and the effects were the strongest in the combination group. Both anlotinib and PD-L1 inhibitor inhibited the growth of transplanted tumors in mice, and the combined group demonstrated the strongest growth suppression. Conclusions: Anlotinib and PD-L1 inhibitor can inhibit cell proliferation, migration, and invasion of TNBC and promote cell apoptosis, and the two drugs show combined anti-tumor effects in vivo and in vitro. The combination of anlotinib and PD-L1 inhibitor may promote apoptosis of TNBC cells through PI3K/AKT/Bcl-xl signaling pathways, which might offer potential clinical treatment roles for these.

Potential prognostic value of the lymph node ratio and its correlation with circulating sex hormone concentration in pathological T1/2 breast cancer patients: a retrospective study.

Background: The lymph node ratio (LNR) is an additional informative factor complementing anatomic TNM staging in breast cancer patients. The aim of this study was to evaluate the role of LNR in the cancer-specific and overall survival (OS) in a cohort of pT1/2 breast cancer patients and examine its correlation with circulating sex hormone concentrations in postmenopausal cases of the cohort from eastern China islands. Methods: Clinical and pathological characteristics, preoperational sex hormone and tumor markers concentrations, and breast cancer-specific survival (BCSS) and OS were analyzed retrospectively in 732 pathological T1/2 breast cancer patients. Results: The LNR was calculated, and the cut-off value was defined as 0.042 by receiver operative characteristic (ROC) curve according to the patient's mortalities. Patients with LNR ≥0.042 exhibited worse BCSS and OS than others (P<0.001) in pT1/2 breast cancer. Among patients with non-triple negative breast cancer (TNBC) and TNBC subtypes, the LNR ≥0.042 group also exhibited worse BCSS and OS than the LNR <0.042 group (P=0.003, 0.001, and P=0.032, 0.001, respectively). In univariate analysis, unfavorable BCSS and OS were both related with LNR ≥0.042 (P=0.001, <0.001). However multivariate analysis demonstrated TNBC subtypes were independent predictor for BCSS and OS [hazard ratio (HR) =1.449, 95% CI: 1.097-1.914, P=0.009; HR =1.365, 95% CI: 1.093-1.705, P=0.006, respectively]. Notably, Pearson or spearman correlation analysis revealed follicle-stimulating hormone (FSH) and, luteinizing hormone (LH) levels were significantly negatively associated with the LNR (P=0.007, 0.011, respectively) in postmenopausal cases, whereas CA153, CA125 and CEA were positively correlated with it (P<0.001, <0.001, 0.001, respectively) in all cases. Conclusions: Among pT1/2 breast cancer patients from eastern China islands, the LNR is a predictive prognosis factor; a higher LNR seems to correlate with a worse survival outcome both overall and in the subgroups. Strikingly, the current results reveal that serum FSH and LH level inversely associated with axillary node invasion in postmenopausal cases, whereas tumor markers directly related with it. The LNR is an informative factor complementing TNM staging.

3D-printed, patient-specific DIEP flap templates for preoperative planning in breast reconstruction: a prospective case series.

BACKGROUND: Modern imaging technologies, such as computed tomographic angiography (CTA), can be useful for preoperative assessment in deep inferior epigastric artery perforator (DIEP) flap surgery. Planning perforator flap design can lead to improved surgical efficiency. However, current imaging modalities are limited by being displayed on a two-dimensional (2D) surface. In contrast, a 3D-printed model provides tactile feedback that facilitates superior understanding. Hence, we have 3D-printed patient-specific deep inferior epigastric artery perforator (DIEP) templates, in an affordable and convenient manner, for preoperative planning. METHODS: Twenty consecutive patients undergoing 25 immediate or delayed post-mastectomy autologous breast reconstruction with DIEP or muscle-sparing transverse rectus abdominis (MS-TRAM) flaps are recruited prospectively. Using free, open-source softwares (3D Slicer, Autodesk MeshMixer, and Cura) and desktop 3D printers (Ultimaker 3E and Moment), we created a template based on a patient's abdominal wall anatomy from CTA, with holes and lines indicating the position of perforators, their intramuscular course and the DIEA pedicle. RESULTS: The mean age of patients was 52 [38-67]. There were 15 immediate and 10 delayed reconstructions. 3D printing time took mean 18 hours and 123.7 g of plastic filament, which calculates to a mean material cost of AUD 8.25. DIEP templates accurately identified the perforators and reduced intraoperative perforator identification by 7.29 minutes (P=0.02). However, the intramuscular dissection time was not affected (P=0.34). Surgeons found the template useful for preoperative marking (8.6/10) and planning (7.9/10), but not for intramuscular dissection (5.9/10). There were no immediate flap-related complications. CONCLUSIONS: Our 3D-printed, patient-specific DIEP template is accurate, significantly reduces intraoperative perforator identification time and, hence, may be a useful tool for preoperative planning in autologous breast reconstruction.

The accuracy of clinical 3D printing in reconstructive surgery: literature review and in vivo validation study.

A growing number of studies demonstrate the benefits of 3D printing in improving surgical efficiency and subsequently clinical outcomes. However, the number of studies evaluating the accuracy of 3D printing techniques remains scarce. All publications appraising the accuracy of 3D printing between 1950 and 2018 were reviewed using well-established databases, including PubMed, Medline, Web of Science and Embase. An in vivo validation study of our 3D printing technique was undertaken using unprocessed chicken radius bones (Gallus gallus domesticus). Calculating its maximum length, we compared the measurements from computed tomography (CT) scans (CT group), image segmentation (SEG group) and 3D-printed (3DP) models (3DP group). Twenty-eight comparison studies in 19 papers have been identified. Published mean error of CT-based 3D printing techniques were 0.46 mm (1.06%) in stereolithography, 1.05 mm (1.78%) in binder jet technology, 0.72 mm (0.82%) in PolyJet technique, 0.20 mm (0.95%) in fused filament fabrication (FFF) and 0.72 mm (1.25%) in selective laser sintering (SLS). In the current in vivo validation study, mean errors were 0.34 mm (0.86%) in CT group, 1.02 mm (2.51%) in SEG group and 1.16 mm (2.84%) in 3DP group. Our Peninsula 3D printing technique using a FFF 3D printer thus produced accuracy similar to the published studies (1.16 mm, 2.84%). There was a statistically significant difference (P<10-4) between the CT group and the latter SEG and 3DP groups indicating that most of the error is introduced during image segmentation stage.

Patent Blue dye allergy and the deep inferior epigastric perforator free flap: a unique interaction.

Patent Blue dye for sentinel lymph node biopsy is associated with systemic allergic response and generalized blue hue. We report a unique case of successful free flap transfer in this setting. Despite inotropic support and abnormal blue hue, allergic response does not preclude safe flap transfer and monitoring.

Enhanced Preoperative Deep Inferior Epigastric Artery Perforator Flap Planning with a 3D-Printed Perforasome Template: Technique and Case Report.

Optimizing preoperative planning is widely sought in deep inferior epigastric artery perforator (DIEP) flap surgery. One reason for this is that rates of fat necrosis remain relatively high (up to 35%), and that adjusting flap design by an improved understanding of individual perforasomes and perfusion characteristics may be useful in reducing the risk of fat necrosis. Imaging techniques have substantially improved over the past decade, and with recent advances in 3D printing, an improved demonstration of imaged anatomy has become available. We describe a 3D-printed template that can be used preoperatively to mark out a patient's individualized perforasome for flap planning in DIEP flap surgery. We describe this "perforasome template" technique in a case of a 46-year-old woman undergoing immediate unilateral breast reconstruction with a DIEP flap. Routine preoperative computed tomographic angiography was performed, with open-source software (3D Slicer, Autodesk MeshMixer and Cura) and a desktop 3D printer (Ultimaker 3E) used to create a template used to mark intra-flap, subcutaneous branches of deep inferior epigastric artery (DIEA) perforators on the abdomen. An individualized 3D printed template was used to estimate the size and boundaries of a perforasome and perfusion map. The information was used to aid flap design. We describe a new technique of 3D printing a patient-specific perforasome template that can be used preoperatively to infer perforasomes and aid flap design.

End-to-End versus End-to-Side Microvascular Anastomosis: A Meta-analysis of Free Flap Outcomes.

Background Optimal outcomes in microsurgery have been attributed to a range of factors, with performing of end-to-end (ETE) versus end-to-side (ETS) influencing anastomotic complications and flap outcomes. Methods A systematic review of the literature and meta-analysis was undertaken to evaluate the relative risks of anastomotic complications with ETE versus ETS approaches, for arterial and venous anastomoses looking at risk ratios (RRs) for thrombosis and overall flap failure. Results RRs of thrombosis and flap failure in ETS versus ETE venous anastomosis groups were 1.30 (95% confidence interval [CI]: 0.53-3.21) and 1.50 (95% CI: 0.85-2.67), respectively. The RRs of thrombosis and flap failure in ETS versus ETE arterial anastomosis groups were 1.04 (95% CI: 0.32-3.35) and 1.04 (95% CI: 0.72-1.48), respectively. Conclusion Differences in rates of thrombosis and flap failure between ETE and ETS venous and arterial anastomoses are marginal and nonsignificant. As such, the type of anastomotic technique is best decided on a case-by-case basis, dependent on anatomical, surgical, and patient factors.

Autologous fat grafting in keloids and hypertrophic scars: a review.

Keloid and hypertrophic scars are unique human dermal fibroproliferative disorders of the injured skin and are associated with pain, itch and can cause functional limitations. A number of genetic, systemic and local factors have been identified in the formation of keloids and hypertrophic scars. Studies have shown that adipose-derived stem cells have angiogenic and antiapoptotic properties which has effects on wound healing, soft-tissue restoration and scar remodelling, and thus may have a role in managing keloid scaring. However, this role is not well described in the literature. A systemic review of available literature was thus undertaken, regarding the use of fat grafting in treatment of keloids and hypertrophic scarring. In total, 858 articles were identified, with ten studies ultimately fulfilling inclusion criteria. There were no studies specifically isolating the keloids and hypertrophic group of patients, and thus quantitative data were completely lacking from the literature. There were, however, individual cases described, and qualitatively encouraging clinical results were reported for the use of fat grafting on keloids and hypertrophic scars. Combined with the current theoretical and immunohistochemical understanding through other laboratory and animal studies, fat grafting may play a role in the treatment of keloids and hypertrophic scaring; however, specific evidence is currently lacking. The role for further research is clear.

Five recipient vessels for metachronous chest wall reconstruction: Case report and literature review.

Selecting potential recipient vessel options for free flap anastomosis is an important consideration in microsurgical breast and chest wall reconstruction. In these settings, the most common comprise the internal mammary and thoracodorsal vessels, although alternative anastomotic sites have also been described. On occasion, consideration of these alternatives becomes a necessity. The use of five separate recipient vessels is highlighted in a unique case of recurrent locally advanced breast cancer requiring multiple complex reconstructions using free tissue transfer. A 56-year-old lady presented for delayed breast reconstruction one year after radical mastectomy for locally advanced lobular breast cancer. Despite wide resections, local chest-wall recurrence five times necessitated five microsurgical reconstructions, using separate recipient pedicles: internal mammary vessels, thoracodorsal vessels, serratus branch of thoracodorsal vessels, intercostal vessels and thoracoacromial vessels. All flaps survived completely, without donor or recipient complications. There has not been a subsequent recurrence at 6 months since last reconstruction. The purpose of this report is to present the first reported case of microsurgical chest wall reconstruction using five separate free flaps requiring anastomosis to multiple recipient vessels for anterior chest wall coverage, to present a literature-based and clinical review of the regional vascular anatomy of the anterior chest wall, and to present an operative approach algorithm. In such complex cases, this understanding can facilitate a streamlined approach to management. © 2014 Wiley Periodicals, Inc. Microsurgery 37:66-70, 2017.

Enhancing breast projection in autologous reconstruction using the St Andrew's coning technique and 3D volumetric analysis.

BACKGROUND: An increasing number of women undergo mastectomy for breast cancer and post-mastectomy autologous breast reconstruction has been shown to significantly improve the psychosexual wellbeing of the patients. A goal of treatment is to achieve symmetry and projection to match the native breast, and/or the contralateral breast in the case of a unilateral reconstruction. Autologous reconstruction, particularly with the deep inferior epigastric artery perforator (DIEP) flap, is particularly advantageous as it can be manipulated to mimic the shape and turgor of the native breast. However, very few techniques of shaping the breast conus when insetting the DIEP flap to enhance aesthetic outcome have been reported to date. With the aide of three-dimension (3D) photography and 3D-printed mirrored image of the contralateral breast as a guide intraoperatively, we describe our St Andrew's coning technique to create a personalized flap projection. METHOD: We report a prospective case series of 3 delayed unilateral breast reconstructions where symmetrization procedure to the contralateral breast was not indicated. Using a commercial 3D scanner (VECTRA XR, Canfield Scientific), the breast region was imaged. The mirrored image was 3D-printed in-house using a desktop 3D printer. RESULTS: In all cases, projection of the breast mound was able to be safely achieved, with a demonstrated central volume (or 'cone') able to be highlighted on imaging and a 3D printed breast. A 3D print of the contralateral breast was able to be used intraoperatively to guide the operative approach. CONCLUSIONS: The St Andrew's coning technique is a useful aesthetic maneuver for achieving breast projection during DIEP flap breast reconstruction, with 3D imaging techniques able to assist in perioperative assessment of breast volume.

A systematic review of intraoperative process mapping in surgery.

Process mapping has been identified as a strategy to improve surgical efficiency but has been inconsistently applied in the literature and underutilised in surgical practice. In this journal, we recently described our utilisation of these approaches when applied to breast reconstruction. We showed that in surgery as complex as autologous breast reconstruction, process mapping can improve efficiency, and may improve surgical teaching, education and audit. The intraoperative period specifically is an area that can be applied not only to breast reconstruction, but to a much broader range of surgical procedures. A systematic review was undertaken of the databases Ovid MEDLINE, Allied and Complementary Medicine Database, Embase and PsychINFO. Manual searching of the references from articles identified was also conducted. Data items relating to the review aims were extracted from articles' methods, applications, and outcomes. A descriptive analysis was carried out to synthesise the information on the current usage of process mapping in the intraoperative period. Seventeen of 1,488 studies were eligible for review, with all of non-randomised study design. Studies had overlap in components of the intraoperative period to which process mapping was applied. Common areas of improvement were identified. Outcome measures were assessed in ten studies that implemented interventions based on the improvement areas to increase surgical efficiency. As such, process mapping has been used as part of larger quality improvement methods, albeit with inconsistent nomenclature, to improve surgical efficiency. While it has been applied to a range of surgical specialties, there is a lack of application to the surgical component of the intraoperative period. Greater consistency in the reporting and description of process mapping will enable further research for evidence of its benefits.

Erratum to comparative study of software techniques for 3D mapping of perforators in deep inferior epigastric artery perforator flap planning.

[This corrects the article on p. 99 in vol. 5, PMID: 27047778.].

3D Volumetric Modeling and Microvascular Reconstruction of Irradiated Lumbosacral Defects after Oncologic Resection.

BACKGROUND: Locoregional flaps are sufficient in most sacral reconstructions. However, large sacral defects due to malignancy necessitate a different reconstructive approach, with local flaps compromised by radiation and regional flaps inadequate for broad surface areas or substantial volume obliteration. In this report, we present our experience using free muscle transfer for volumetric reconstruction, in such cases, and demonstrate three-dimensional (3D) haptic models of the sacral defect to aid preoperative planning. METHODS: Five consecutive patients with irradiated sacral defects secondary to oncologic resections were included, surface area ranging from 143-600 cm2. Latissimus dorsi (LD)-based free flap sacral reconstruction was performed in each case, between 2005 and 2011. Where the superior gluteal artery was compromised, the subcostal artery (SA) was used as a recipient vessel. Microvascular technique, complications, and outcomes are reported. The use of volumetric analysis and 3D printing is also demonstrated, with imaging data converted to 3D images suitable for 3D printing with Osirix software (Pixmeo, Geneva, Switzerland). An office-based, desktop 3D printer was used to print 3D models of sacral defects, used to demonstrate surface area and contour and produce a volumetric print of the dead space needed for flap obliteration. RESULTS: The clinical series of LD free flap reconstructions is presented, with successful transfer in all cases, and adequate soft-tissue cover and volume obliteration achieved. The original use of the SA as a recipient vessel was successfully achieved. All wounds healed uneventfully. 3D printing is also demonstrated as a useful tool for 3D evaluation of volume and dead space. CONCLUSION: Free flaps offer unique benefits in sacral reconstruction where local tissue is compromised by irradiation and tumor recurrence, and dead space requires accurate volumetric reconstruction. We describe for the first time the use of the SA as a recipient in free flap sacral reconstruction. 3D printing of haptic bio-models is a rapidly evolving field with a substantial role in preoperative planning.

3D haptic modelling for preoperative planning of hepatic resection: A systematic review.

INTRODUCTION AND BACKGROUND: Three dimensional (3D) printing has gained popularity in the medical field because of increased research in the field of haptic 3D modeling. We review the role of 3D printing with specific reference to liver directed applications. METHODS: A literature search was performed using the scientific databases Medline and PubMed. We performed this in-line with the PRISMA [20] statement. We only included articles in English, available in full text, published about adults, about liver surgery and published between 2005 and 2015. The 3D model of a patient's liver venous vasculature and metastasis was prepared from a CT scan using Osirix software (Pixmeo, Gineva, Switzerland) and printed using our 3D printer (MakerBot Replicator Z18, US). To validate the model, measurements from the inferior vena cava (IVC) were compared between the CT scan and the 3D printed model. RESULTS: A total of six studies were retrieved on 3D printing directly related to a liver application. While stereolithography (STL) remains the gold standard in medical additive manufacturing, Fused Filament Fabrication (FFF), is cheaper and may be more applicable. We found our liver 3D model made by FFF had a 0.1 ± 0.06 mm margin of error (mean ± standard deviation) compared with the CT scans. CONCLUSION: 3D printing in general surgery is yet to be thoroughly exploited. The most relevant feature of interest with regard to liver surgery is the ability to view the 3D dimensional relationship of the various hepatic and portal veins with respect to tumor deposits when planning hepatic resection. Systematic review registration number: researchregistry1348.