Evaluation of aesthetic outcomes of mandibular reconstruction using artificial intelligence.

BACKGROUND: Although vascularized bone graft (VBG) transfer is the current standard for mandibular reconstruction, reconstruction with a mandibular reconstruction plate (MRP) and with a soft-tissue flap (STF) alone remain crucial options for patients with poor general conditions. However, objective aesthetic outcome evaluations for these methods are limited. METHODS: In a retrospective analysis of 65 patients (VBG, 33; MRP, 19; and STF, 13), mandibular asymmetry value was calculated for each patient's photograph using facial recognition AI, with a higher value indicating worse asymmetry. RESULTS: The MRP group had a value comparable to the VBG group regardless of mandibular defect types. The STF group had a significantly higher value than the VBG group. CONCLUSIONS: Regarding cosmesis, STF was inferior to VBG, whereas MRP was comparable to VBG, even for anterior defects for which rigid reconstruction is mandatory. However, MRP's risks of plate-related complications limit its use to cases where VBG is contraindicated or with poor prognosis.

Early enteral nutrition and mobilization following head and neck surgery with free flap reconstruction.

BACKGROUND: Perioperative management methods that reduce surgery-associated invasiveness and improve the quality of postoperative recovery are being promoted as enhanced recovery after surgery programs in various areas. Early enteral nutrition and mobilization are essential elements for enhanced recovery after surgery; however, their safety and feasibility are unclear in head and neck surgery with free tissue transfer reconstruction. This study aimed to clarify these uncertainties. METHODS: This is a retrospective before-after study. From 2018 to 2022, 187 and 173 patients received conventional management on or before April 2020 and early management on or after May 2020, respectively. The conventional management and early management groups received enteral nutrition and mobilization on postoperative days 2 and 1, respectively. The primary outcome for safety assessment was the incidence of complications. The secondary outcome was the compliance rate of conventional management or early management for feasibility assessment and the length of hospital stay. RESULTS: The clinical tumour-node-metastasis stage and American Society of Anesthesiologists physical status showed significant differences between the groups. In multivariable analysis, the early management group demonstrated a significantly lower incidence of treatment-required complication classified Clavien-Dindo Grade 2 and above (odds ratio = 0.57; 95% confidence interval = 0.31-0.92) and lower wound infection (odds ratio = 0.53; 95% confidence interval = 0.31-0.92). The early management group had lower compliance rate than the conventional management group; however, no statistically significant difference was observed (79.8% vs. 85.0%, P = 0.21). CONCLUSION: Early management is safe and feasible following head and neck surgery with free tissue transfer reconstruction. It could reduce the complication rate and is considered a useful postoperative management method.

Machine learning approach to predict tracheal necrosis after total pharyngolaryngectomy.

BACKGROUND: Tracheal necrosis is a potentially severe complication of total pharyngolarynjectomy (TPL), sometimes combined with total esophagectomy. The risk factors for tracheal necrosis after TPL without total esophagectomy remain unknown. METHODS: We retrospectively reviewed data of 395 patients who underwent TPL without total esophagectomy. Relevant factors associated with tracheal necrosis were evaluated using random forest machine learning and traditional multivariable logistic regression models. RESULTS: Tracheal necrosis occurred in 25 (6.3%) patients. Both the models identified almost the same factors relevant to tracheal necrosis. History of radiotherapy was the most important predicting and significant risk factor in both models. Paratracheal lymph node dissection and total thyroidectomy with TPL were also relevant. Random forest model was able to predict tracheal necrosis with an accuracy of 0.927. CONCLUSIONS: Random forest is useful in predicting tracheal necrosis. Countermeasures should be considered when creating a tracheostoma, particularly in patients with identified risk factors.

Second free jejunum transfer after flap loss does not affect oral intake: A retrospective case-control study.

PURPOSE: Free jejunum transfer is one of the standard procedures for restoring oral intake after total pharyngo-laryngo-esophagectomy. Flap loss leading to a second free jejunum transfer rarely occurs. This study investigated the impact of a second free jejunum transfer on post-operative oral intake. METHODS: A retrospective review was conducted on patients who underwent a first free jejunum transfer between July 1998 and December 2019. A total of 367 patients were included in the study. Among them, 17 patients who underwent a second free jejunum transfer because necrosis constituted the second free jejunum transfer group, whereas 350 patients who did not require a second free jejunum transfer formed the first free jejunum transfer group. The incidence of dysphagia requiring tube feeding and post-operative complications was compared between the two groups. Moreover, risk factors for dysphagia and complications were estimated. RESULTS: There were no statistically significant differences in the incidence of dysphagia post-operation between the two groups. A second free jejunum transfer was a statistically significant factor for complications at 2- and 6-months post-operation; however, there were no significant differences in complication rates at the 12-month follow-up. Furthermore, there were no significant differences in the incidence of severe complications between the two groups. CONCLUSION: Although a second free jejunum transfer increases early complications, it is not associated with major complications and does not negatively impact oral intake. These findings support the conclusion that free jejunum transfer is safe and helps maintain post-operative quality of life.

Clinical assessment of early mobilization after head and neck free flap reconstruction: A retrospective case-control study.

PURPOSE: We examined whether there were any differences in perioperative complications between patients who mobilized on the first postoperative day (early mobilization) and those who mobilized on the second postoperative day after head and neck reconstruction using free tissue transfer. METHODS: In the control group (n = 74), patients were instructed to mobilize on the second postoperative day (April 2019-March 2020), while in the early mobilization group (n = 101), patients were instructed to mobilize on the first postoperative day (April 2020-March 2021). Mobilization was defined as maintaining a standing position or walking. Clinical data were collected from medical records and retrospectively analyzed. RESULTS: There were no significant differences in clinical background factors, with the exception of intraoperative blood loss volume. The proportion of patients who successfully mobilized on the day of instruction was significantly lower in the early mobilization group (89.1% vs. 98.7%). One case of total flap loss and four cases of partial flap loss occurred in the control group, and three cases of partial flap loss occurred in the early mobilization group. There was no significant difference in partial or total flap loss between the two groups. There were no significant differences in other perioperative complications (wound infection, postoperative bleeding, and delirium) between the two groups. The median postoperative hospital stay was 24.5 and 25.0 days in the control and early mobilization groups, respectively. CONCLUSION: In this study, early mobilization on the first day after head and neck free flap reconstruction was safe and feasible.

Mechanism of Budded Virus Envelope Fusion into a Planar Bilayer Lipid Membrane on a SiO2 Substrate.

Artificial planar bilayer lipid membranes (BLMs) are simple models of cellular systems under physically and chemically controlled conditions, and they have been used to investigate membrane protein activity. Baculovirus-budded virus (BV) systems can express recombinant membrane proteins. In this study, aiming for membrane protein reconstitution, we examined the fusion of BVs containing recombinant membrane proteins into artificial planar BLMs on a Si microwell substrate. BV fusion with the BLMs depended on the pH of the solution, and it was enhanced at lower pH. Based on fluorescence recovery after photobleaching (FRAP) measurement, the fusion state of BVs was evaluated, and full fusion at low pH was confirmed. The fluorescent labeling the membrane proteins was also observed in the freestanding part of the BLMs as well as in the supported part. These results demonstrate the effectiveness of BLMs as a platform to examine detailed fusion dynamics of BVs. Furthermore, this study revealed that the fusion of BVs is a promising method for reconstituting membrane proteins to artificial freestanding BLMs for the development of biodevices with which we can examine membrane protein activity.

Surgical Outcome of Pharyngocutaneous Fistula After Total Laryngectomy: A Retrospective Study.

BACKGROUND: The management of pharyngocutaneous fistula is challenging. We typically treat postlaryngectomy pharyngocutaneous fistulas with a pedicled pectoralis major flap transfer. This study analyzed the outcomes of our surgical treatments for pharyngocutaneous fistula to propose considerations for surgical strategies. METHODS: This retrospective review included all patients who underwent surgical repair of a postlaryngectomy pharyngocutaneous fistula at the National Cancer Center Hospital East in Kashiwa, Japan, from January 2005 to December 2019. RESULTS: The final analysis included 33 cases (median age, 71 years). Twenty-two cases had a history of radiotherapy to the head and neck region. Wound closures were performed with a pedicled pectoralis major musculocutaneous flap (n = 26) or pedicled pectoralis major muscle flap (n = 7). In 1 case, a deltopectoral flap was combined with the pectoralis major musculocutaneous flap. The median total operation time was 236 minutes, the median blood loss during surgery was 144 mL, and the median hospital stay after the reconstructive surgery was 39 days. Minor leakage occurred in 19 cases, and major leakage occurred in 2 cases. The fistula was finally cured successfully in 31 cases. We compared the outcomes in patients with leakage after surgical repair to those in patients without leakage after surgical repair to determine the risk factors for leakage after surgical repair of a pharyngocutaneous fistula. Five patients in the nonleakage group and 17 in the leakage group had a history of preoperative radiation (P = 0.052). The median preoperative blood values in the nonleakage and leakage groups were as follows: albumin, 3.6 and 3.2 g/dL (P = 0.061), and C-reactive protein, 2.36 and 6.77 mg/dL (P = 0.031), respectively. The time between the occurrence of the fistula and reconstructive surgery was 32 and 9 days in the nonleakage and leakage groups, respectively (P = 0.009). CONCLUSIONS: Our surgical treatment for postlaryngectomy pharyngocutaneous fistula succeeded in 31 of 33 cases (94%). This study demonstrated that pedicled pectoralis major flap transfer is useful for the treatment of postlaryngectomy pharyngocutaneous fistula.

Surgical outcome for colorectal or urinary tract-related fistula: Usefulness of vascularized tissue transfer-a retrospective study⁎.

BACKGROUND: It is challenging to manage colorectal or urinary tract-related fistula. We typically treat colorectal or urinary tract-related fistula with a vascularized tissue transfer. This study aimed to analyze the outcomes of our surgical treatments for colorectal or urinary tract-related fistula. METHODS: This retrospective review included all patients who underwent surgical repair of a colorectal or urinary tract-related fistula at our institution from October 2004 to September 2019. Patients whose surgical outcomes could not be evaluated were excluded. The primary outcome was the overall cure rate. We also evaluated the complication rate and compared the outcomes for rectovaginal fistula with those for urorectal fistula. RESULTS: The final analysis included 38 cases, of which 17 were rectovaginal fistula and 16 were urorectal fistula. The transperineal approach was used in 28 cases and transperineal and transabdominal combined in nine cases. A gracilis muscle flap was used in 19 cases and a gluteal fold flap in 13 cases. Although a major leak occurred in nine cases, the fistula was finally cured successfully in 31 cases. A comparison of the outcomes for rectovaginal fistula and urorectal fistula showed that complications occurred in 5/17 cases of rectovaginal fistula and 10/16 cases of urorectal fistula (p = 0.056). Fistulae were cured successfully in 13/17 cases of rectovaginal fistula and 14/16 cases of urorectal fistula (p = 0.656). CONCLUSION: Our surgical treatment for colorectal or urinary tract-related fistula succeeded in 31 of 38 cases. Thus, vascularized tissue transfer is useful for refractory colorectal or urinary tract-related fistula.

Crystalline and Electrical Property Improvement of Filtrated, Exfoliated Graphite Sheets by an In-Plane Current and Heating Treatment.

We report an approach to fabricate high conductivity graphite sheets based on a heat-and-current treatment of filtrated, exfoliated graphite flakes. This treatment combines heating (~ 900 °C) and in-plane electrical current flow (550 A·cm-2) to improve electrical conductivity through the reduction of crystalline defects. This process was shown to require only a 1-min treatment time, which resulted in a 2.1-fold increase in electrical conductivity (from 1088 ± 72 to 2275 ± 50 S·cm-1). Structural characterization by Raman spectroscopy and X-ray diffraction indicated that the improvement electrical conductivity originated from a 30-fold improvement in the crystallinity (Raman G/D ratio increase from 2.8 to 85.3) with no other observable structural transformations. Significantly, this treatment was found to act uniformly across a macroscopic (10 mm) sheet surface indicating it is on the development of applications, such as electrodes for energy generation and storage and electromagnetic shielding, as well as on the potential for the development of large-scale treatment technologies.

Evaluation of Lateral Diffusion of Lipids in Continuous Membranes between Freestanding and Supported Areas by Fluorescence Recovery after Photobleaching.

The lateral diffusion of lipids is a key factor when functionalizing artificial planar bilayer lipid membranes (BLMs). Fluorescence recovery after photobleaching (FRAP) is an established method for evaluating the fluidity of BLMs by the quantitative determination of the diffusion coefficient. However, a BLM with a uniform diffusion coefficient is usually assumed for analysis. In addition, when the BLM to be evaluated is small, the spread of a bleached circle caused by lateral diffusion during the bleaching process and the divergence of the laser used for bleaching interfere with the quantitative analysis. In this study, a numerical calculation was adopted to make it possible to analyze the continuous BLM between freestanding and supported areas, where the diffusion coefficients change depending on the presence or absence of an interaction with the substrate. A quantitative evaluation independent of such bleaching conditions as the bleaching diameter was also ensured by incorporating the spreading effect of the bleached circle in the calculation, which was employed to analyze a freestanding BLM with a diameter of only a few micrometers. By comparing calculations and experiments on FRAP recovery curves, we found that there are multiple diffusion elements and high diffusion barriers at the boundary between the freestanding and supported areas in a BLM over a SiO2/Si microwell substrate.

One millimeter per minute growth rates for single wall carbon nanotube forests enabled by porous metal substrates.

We report an exceptionally high-efficiency synthesis of long single-wall carbon nanotube (SWCNT) forests using porous substrates (metal meshes) in place of nonporous flat substrates. This study examined the dependence of the growth efficiency on various mesh structures, including wire diameter, aperture size, and total surface area. We demonstrated that the synthesis of SWCNT forests is highly dependent on the initial porosity as well as maintaining the open pores throughout the duration of the growth. Our results show that carbon nanotubes (CNTs) can be grown on all surfaces of the mesh in high efficiency with the optimum growth efficiency observed for a mesh porosity of ∼30%. Based on these results, we demonstrated the high efficiency synthesis of SWCNT forests (height: >3.47 mm, average growth rate: 301 µm min-1, and yield: 12.7 mg cm-2 in 10 min growth time). Furthermore, we showed that the initial growth rates exceeded 1 millimeter per minute (1000 µm min-1). Our results further indicate that metal meshes represent a viable alternative to nonporous flat substrates for the efficient synthesis of tall and high yielding SWCNTs.

Stripped Mesenteric Flap: A Novel Option for Preventing Anastomotic Leakage in Circumferential Pharyngeal Reconstruction.

Reconstruction of a circumferential pharyngeal defect with a free jejunal flap is a well-established procedure. However, anastomotic leakage often occurs, which can lead to abscess formation, pharyngocutaneous fistula formation, and carotid rupture. Previous reports have described covering the anastomotic site with a mesenteric flap to prevent anastomotic leakage. However, the mesentery is covered by a serosal membrane, which interferes with adhesion and vascular communication. Therefore, we stripped off the serosal membrane to accelerate adhesion to the anastomotic site. We retrospectively studied patients who had a history of radiotherapy and who had received a stripped mesenteric flap in a circumferential pharyngeal reconstruction procedure. We collected the following data: operative time, blood loss, postoperative complications, interval to resumption of oral intake, and duration of hospital stay. We obtained data for 11 patients. The jejunal flap failed in one patient because of arterial thrombosis. One of the other 10 patients developed anastomotic leakage caused by congested mucous membrane necrosis. The patient was treated conservatively and showed no clinical symptoms of infection or inflammation. The 9 remaining patients had no anastomotic leakage. In the present series, although anastomotic leakage was observed in one of 10 patients who underwent circumferential pharyngeal reconstruction using a stripped mesenteric flap, the severity of the leakage was minimized.

Liquid-Ordered/Liquid-Crystalline Phase Separation at a Lipid Bilayer Suspended over Microwells.

The localization of liquid-ordered (Lo) and liquid-crystalline (Lα) phase domains on a silicon substrate with a microwell array is investigated. Although the phase separation of the Lo and Lα phases on both a giant unilamellar vesicle (GUV) and a supported membrane remains stable for a long time, the lateral diffusion of lipids across each domain boundary occurs quickly. Since the phase separation and domain arrangement are governed by the stiffness and lateral tension of the lipid membrane, the phase separation is rearranged on a micropatterned substrate. Similar phase separation of the Lo and Lα phases is observed at a lipid membrane suspended over a microwell. However, the Lα phase is preferred at a suspended membrane, and saturated lipids and cholesterol are excluded toward the supporting membrane on the periphery. Since the Lo domain area is reduced by anisotropic diffusion through the boundary between the suspended and supported membranes, a very slow reduction rate with a linear functional relation is observed. Finally, a localized Lα phase domain is observed at a membrane suspended over a microwell, which is surrounded by an Lo phase supported membrane.

Vesicle fusion with bilayer lipid membrane controlled by electrostatic interaction.

The fusion of proteoliposomes is a promising approach for incorporating membrane proteins in artificial lipid membranes. In this study, we employed an electrostatic interaction between vesicles and supported bilayer lipid membranes (s-BLMs) to control the fusion process. We combined large unilamellar vesicles (LUVs) containing anionic lipids, which we used instead of proteoliposomes, and s-BLMs containing cationic lipids to control electrostatic interaction. Anionic LUVs were never adsorbed or ruptured on the SiO2 substrate with a slight negative charge, and selectively fused with cationic s-BLMs. The LUVs can be fused effectively to the target position. Furthermore, as the vesicle fusion proceeds and some of the positive charges are neutralized, the attractive interaction weakens and finally the vesicle fusion saturates. In other words, we can control the number of LUVs fused with s-BLMs by controlling the concentration of the cationic lipids in the s-BLMs. The fluidity of the s-BLMs after vesicle fusion was confirmed to be sufficiently high. This indicates that the LUVs attached to the s-BLMs were almost completely fused, and there were few intermediate state vesicles in the fusion process. We could control the position and amount of vesicle fusion with the s-BLMs by employing an electrostatic interaction.

Comparison of Donor Site Drainage Duration and Seroma Rate Between Latissimus Dorsi Musculocutaneous Flaps and Thoracodorsal Artery Perforator Flaps.

INTRODUCTION: Donor site seroma formation and prolonged drainage duration are common complications of using latissimus dorsi musculocutaneous (LDMC) flaps. The present retrospective study aimed to investigate the effect of types of back flap harvest on drainage duration and seroma formation rates. METHODS: Adult patients (n = 155) who underwent reconstruction with a latissimus dorsi flap from January 2010 to October 2015 were included in the study, of which 54 patients underwent breast reconstruction with a pedicled LDMC flap (LD breast group), 80 patients underwent an LDMC flap transfer for purposes other than breast reconstruction (LD nonbreast group), and 21 patients underwent soft tissue reconstruction with a thoracodorsal artery perforator (TAP) flap (TAP group). Flap size, drainage durations, and seroma formation rates at donor sites were compared among the 3 groups. RESULTS: Flap sizes significantly differed between the LD nonbreast group (median value, 185.5 cm) and the other 2 groups (119 cm in the LD breast group. 127.5 cm in the TAP group), with no significant difference observed between the LD breast and TAP groups. The mean drainage duration was 11.6 days for the LD breast group. 9.82 days for the LD nonbreast group, and 4.81 days for the TAP group. Drainage durations significantly differed among the groups. Seroma formation rate of the LD breast group (42.6%) was significantly higher than those of the other groups. CONCLUSIONS: The type of back flap harvest used significantly affected drainage duration and seroma formation rate in the present study. Lumbar fat extension with the use of a LDMC flap for breast reconstruction may lead to seroma formation. Thoracodorsal artery perforator flaps are associated with minimal risks of seroma formation and significantly shortened drainage duration compared with LDMC flaps.

Reconstructive Surgery for Bronchopleural Fistula and Empyema: New Application of Free Fascial Patch Graft Combined with Free Flap.

BACKGROUND: Postoperative bronchopleural fistula (BPF) and empyema are not uncommon after lung cancer surgery. Some patients require reconstructive surgery to achieve wound healing. In this report, we describe a novel method of reconstructive surgery for BPF and empyema. METHODS: From 1996 through 2014, we performed reconstructive surgery for the treatment of BPF and empyema in 13 cases. BPF or a pulmonary fistula was present in 11 patients at the time of reconstruction. Of these, a free fascial patch graft combined with a free soft tissue flap was used to close the fistula in 6 cases. In the other 5 cases, primary fistula closure or direct coverage of the fistula with a transferred flap was performed. Medical records were retrospectively reviewed, and postoperative results were compared for these methods. RESULTS: All the flaps were transferred successfully except in 1 case. Although postoperative air leakage was observed in 5 cases, most of these healed with conservative management. Of 11 fistulas, 8 were successfully controlled. Although differences were not statistically significant, a higher success rate of fistula closure was obtained in patients with a fascial patch graft (100% vs 40%). As a result, 9 patients could be discharged from the hospital, but 4 died during their hospital stay. CONCLUSION: Although the incidence of in-hospital mortality was high, fistula closure with a fascial patch graft combined with free flap transfer was effective for the treatment of BPF and empyema, compared with other procedures.

Analysis of functional outcomes in patients with mandible reconstruction using vascularized fibular grafts.

BACKGROUNDS: Although a vascularized fibular graft (VFG) is the favored method for mandible reconstruction, only few functional reports have been published. In this study, surgical outcomes and functional results after mandible reconstruction were analyzed. PATIENTS AND METHODS: From 1999 through 2010, oromandibular defects after segmental mandibulectomy were reconstructed with VFG in 101 patients. Operative outcomes and subjective functional evaluation was performed. Of these, 44 patients could be evaluated for functional outcomes, and bite force was measured with an occlusal force meter in 24 patients. RESULTS: Major surgical complications required secondary revisional surgery developed in four patients. A normal diet was possible in 37 patients (84.1%), and a soft diet was possible in 7 patients (15.9%). Conversational ability was rated as excellent in 42 patients (95.5%). The mean bite force on the nonaffected side of the mandible was 187.7 N, and bite force decreased as the number of osteotomies in the VFG increased. Furthermore, bite force was significantly lower (P = 0.001) on the affected side (58.2 N), compared to nonaffected side (191.9 N). CONCLUSIONS: Although masticatory force decreases as the number of osteotomies increases, oral function after mandible reconstruction is satisfactory in most cases. Transfer of a VFG is a safe and reliable method for functional mandible reconstruction. © 2015 Wiley Periodicals, Inc. Microsurgery 37:101-104, 2017.

A DNA aptamer recognising a malaria protein biomarker can function as part of a DNA origami assembly.

DNA aptamers have potential for disease diagnosis and as therapeutics, particularly when interfaced with programmable molecular technology. Here we have combined DNA aptamers specific for the malaria biomarker Plasmodium falciparum lactate dehydrogenase (PfLDH) with a DNA origami scaffold. Twelve aptamers that recognise PfLDH were integrated into a rectangular DNA origami and atomic force microscopy demonstrated that the incorporated aptamers preserve their ability to specifically bind target protein. Captured PfLDH retained enzymatic activity and protein-aptamer binding was observed dynamically using high-speed AFM. This work demonstrates the ability of DNA aptamers to recognise a malaria biomarker whilst being integrated within a supramolecular DNA scaffold, opening new possibilities for malaria diagnostic approaches based on DNA nanotechnology.

Scalability of the Heat and Current Treatment on SWCNTs to Improve their Crystallinity and Thermal and Electrical Conductivities.

We have investigated the scalability of our post-synthesis graphitization process for single-walled carbon nanotubes (SWCNTs), which applies heat and current to SWCNTs to improve the thermal and electrical conductivities. This investigation was performed by examining the relationship between the processing conditions and the amount of treated SWCNTs. Characterization of all cases of treated SWCNTs showed the same level of improvement of ~3 times to both the thermal and electrical conductivities and that the SWCNTs remained SWCNTs, i.e., no change in diameter or wall number. These results provided evidence that the ability to improve the crystallinity of the SWCNTs was independent of the treatment amount. Further, our results showed that an increase in SWCNT amount required increased applied current density or increased in applied temperature to achieve optimum property improvement. Finally, we found a trade-off between the current density and temperature indicating that either a high current or high temperature was required to achieve the optimum process conditions. These results demonstrated that our heat and current SWCNT treatment was fundamentally scalable and applied towards larger scale (i.e., gram-level or more) amounts of SWCNT.