Biomechanical properties of the ex vivo porcine trachea: A benchmark for three-dimensional bioprinted airway replacements.

PURPOSE: Combining tissue engineering and three-dimensional (3D) printing may allow for the introduction of a living functional tracheal replacement graft. However, defining the biomechanical properties of the native trachea is a key prerequisite to clinical translation. To achieve this, we set out to define the rotation, axial stretch capacity, and positive intraluminal pressure capabilities for ex vivo porcine tracheas. STUDY DESIGN: Animal study. MATERIALS AND METHODS: Six full-length ex vivo porcine tracheas were bisected into 5.5 cm segments. Maximal positive intraluminal pressure was measured by sealing segment ends with custom designed 3D printed caps through which a pressure transducer was introduced. Axial stretch capacity and rotation were evaluated by stretching and rotating the segments along their axis between two clamps, respectively. RESULTS: Six segments were tested for axial lengthening and the average post-stretch length percentage was 148.92% (range 136.81-163.48%, 95% CI 153-143%). The mean amount of length gain achieved per cartilaginous ring was 7.82% (range 4.71-10.95%, 95% CI 6.3-9.35%). Four tracheal segments were tested for maximal positive intraluminal pressure, which was over 400 mmHg. Degree of rotation testing found that the tracheal segments easily transformed 180° in anterior-posterior bending, lateral bending, and axial rotational twisting. CONCLUSIONS: We define several biomechanical properties of the ex vivo porcine trachea by reporting the rotation, axial stretch capacity, and positive intraluminal pressure capabilities. We hope that this will aid future work in the clinical translation of 3D bioprinted airway replacement grafts and ensure their compatibility with native tracheal properties.

Robotic hiatal hernia repair without mesh.

Background: Newer minimally invasive techniques have supplanted laparotomy and thoracotomy for management of hiatal hernias. Limited data exists on outcomes after robotic hiatal hernia repair without mesh despite the increasing popularity of this approach. We report our high-volume experience with durable robotic hiatal hernia repair with gastric fundoplication without mesh. Methods: A retrospective review was conducted on patients with type I-IV hiatal hernias who underwent an elective robotic-assisted repair from 2016 to 2019 using a novel technique of approximating the hiatus with running barbed absorbable (V-locTM) suture and securing it with interrupted silk sutures. Main outcomes included length of stay, readmission rate, and recurrence rate. Results: A total of 144 patients were reviewed. The average age of the patient was 61 years. Most of the patients were female [95 females (66%) to 49 males], and the average body mass index (BMI) was 29.96 kg/m2. The average operating time was 173 minutes (standard deviation 62 minutes). The average length of stay in the hospital was 2 days, and 89% of patients went home within the first 3 days. Ten patients (6.9%) were readmitted within 30 days, there were no mortalities in 30 days, and there were 6 (4.2%) recurrences on follow up requiring reoperation. Conclusions: Elective robotic hiatal hernia repair with fundoplication and primary closure of the hiatus with V-locTM and nonabsorbable suture without mesh is safe and effective. The robotic approach has similar operative times, lengths of stay, and complications compared to nationally published data on laparoscopic hiatal hernia repairs.

Safety and usability of an endo staple line reinforcement device for pulmonary resections.

Background: Pulmonary resection can present technical challenges for surgeons due to the dissection and closure of tissues, which vary in thickness and elastic properties, occasionally leading to prolonged air leaks. Staple line reinforcements (SLRs) are widely utilized tools for fortifying the stability and integrity of closures in thoracic surgery, however, materials available and ease of use for both surgeon and scrub nurse have been suboptimal. A novel "click-and-go" device pre-loaded with bioabsorbable buttress material was recently developed, the Echelon Endopath SLR (ESLR, Ethicon, Inc., Cincinnati, OH, USA). This prospective study examines the safety and efficacy of this novel device in lung resections. Methods: Adult surgical candidates undergoing primary pulmonary resection (both open and thoracoscopic) where the ESLR would be used were enrolled. Exclusion included reoperation/revision in same anatomical location, hypersensitivity to polyglactin or related products, and body mass index (BMI) ≥46.0 kg/m2. The primary endpoint assessed the incidence of specific device-related adverse events (AEs): prolonged air leak and empyema. Additional endpoints included number of devices replaced during surgery due to slippage or bunching, and surgeon-reported usability responses. Data was summarized for AEs deemed device-related and usability questionnaire responses. Results: A total of 131 subjects were included in the primary endpoint analysis data set with 120 subjects completing the study (91.6%). The mean age at consent was 62.8±12.0 years and 55.7% were female. The most common primary indication for the procedure was malignancy 61.1%, and primary non-malignant lung disease (non-chronic obstructive pulmonary disease) 12.2%. Common procedures performed were wedge resection (58.0%) and lobectomy (34.4%). There were zero reported device-specific/-related AEs which counted toward the primary endpoint. Responses from a usability questionnaire found all surgeons (100.0%) reported the ease of setup was superior to previous devices utilized. Surgeons expressed greater confidence in the buttress material of the ESLR than that of previous SLR devices (strongly agree 88.9%; slightly agree 11.1%). Most also felt that there was less wastage with the click-and-go ESLR (strongly agree 77.8%, slightly agree 11.1%, neutral 11.1%). Conclusions: The ESLR device demonstrates safe and effective performance in this post-market study of specific thoracic procedures. Furthermore, surgeons found this was easier to use.

A two-stage in vivo approach for implanting a 3D printed tissue-engineered tracheal replacement graft: A proof of concept.

OBJECTIVES: To optimize a 3D printed tissue-engineered tracheal construct using a combined in vitro and a two-stage in vivo technique. METHODS: A 3D-CAD (Computer-aided Design) template was created; rabbit chondrocytes were harvested and cultured. A Makerbot Replicator™ 2x was used to print a polycaprolactone (PCL) scaffold which was then combined with a bio-ink and the previously harvested chondrocytes. In vitro: Cell viability was performed by live/dead assay using Calcein A/Ethidium. Gene expression was performed using quantitative real-time PCR for the following genes: Collagen Type I and type II, Sox-9, and Aggrecan. In vivo: Surgical implantation occurred in two stages: 1) Index procedure: construct was implanted within a pocket in the strap muscles for 21 days and, 2) Final surgery: construct with vascularized pedicle was rotated into a segmental tracheal defect for 3 or 6 weeks. Following euthanasia, the construct and native trachea were explanted and evaluated. RESULTS: In vitro: After 14 days in culture the constructs showed >80% viable cells. Collagen type II and sox-9 were overexpressed in the construct from day 2 and by day 14 all genes were overexpressed when compared to chondrocytes in monolayer. IN VIVO: By day 21 (immediately before the rotation), cartilage formation could be seen surrounding all the constructs. Mature cartilage was observed in the grafts after 6 or 9 weeks in vivo. CONCLUSION: This two-stage approach for implanting a 3D printed tissue-engineered tracheal replacement construct has been optimized to yield a high-quality, printable segment with cellular growth and viability both in vitro and in vivo.

TRALI Syndrome Complicated by Retroperitoneal Bleeding.

Transfusion-related acute lung injury (TRALI) is an underdiagnosed and underreported syndrome which by itself is the third leading cause of transfusion-related mortality. The incidence of TRALI is reported to be 1 in 2000 to 5000 transfusions. When combined with uncontrollable bleeding, survival is unachievable. We report the case of a 25-year-old man, who underwent open heart surgery as an infant to correct his congenital heart disease in association with right pulmonary artery atresia. He presented with hemoptysis secondary to aspergilloma and required a pneumonectomy of the nonfunctional right lung. During pneumolysis, significant bleeding occurred from the superior vena cava. The patient required a blood transfusion and was placed on cardiopulmonary bypass to control the bleeding. Simultaneous occurrence of severe pulmonary edema and retroperitoneal bleeding were noted. Approximately 8 L of frothy edema fluid were drained from the only functional left lung starting ~15 minutes after the transfusion and lasting for several hours until the end of the case. It most likely represented TRALI syndrome. Increasing abdominal girth and poor volume return to the pump were consistent with and pathognomonic for retroperitoneal bleeding. Though primary surgical bleeding in the chest was controlled successfully and a pneumonectomy performed without further difficulty, we were unable to separate the patient from cardiopulmonary bypass due to the inability to oxygenate. As a result, we could not reverse the anti-coagulation which potentially exacerbated the retroperitoneal bleeding. After multiple unsuccessful attempts the patient succumbed. This ill-fated case demonstrates the quandary of obtaining vascular access for emergency cardiopulmonary bypass while in the right thoracotomy position. It may be beneficial to have both the femoral artery and vein cannulated before positioning a patient in a lateral decubitus position. In addition, early direct access to the right atrium may obviate a need for femoral venous cannulation. Also, adult extracorporeal membrane oxygenation may be indicated if faced with such a severe pulmonary edema without ongoing hemorrhage.

Impact That Day of the Week has on Length of Stay for Video-assisted Lobectomy.

We aimed to analyze the effect that the day of the week for video-assisted thoracoscopic surgery lobectomy has on length of stay . A retrospective review identified all patients who underwent video-assisted thoracoscopic surgery lobectomy at a single institution from January 2016 to July 2017. In total, 208 patients were divided into 2 groups based on timing of their operation: Operations performed on Monday, Tuesday, or Wednesday were defined as "early in the week" and those performed on Thursday or Friday were defined as "late in the week." We then propensity-matched 81 pairs of patients and analyzed perioperative data and short-term clinical outcomes. A total of 208 patients underwent video-assisted thoracic surgery lobectomy during the study period. Length of stay was significantly decreased by 2.0 days (P <0.0001) for all lobectomies performed "early in the week" compared with those performed "late in the week." Thirty-day mortality and all major morbidities did not significantly different between the 2 matched groups. Our findings suggest that major pulmonary resections should be performed early in the week, when feasible, to facilitate utilization of hospital resources and prompt discharge.

Uniportal VATS Lobectomy and Decortication: Not an Everyday Occurrence.

Management of trapped lung with an underlying lung lesion and hydropneumothorax remains controversial. Furthermore, Aspergillus empyema and aspergilloma are rare pathologies for which uniportal video-assisted thoracoscopic (VATS) surgical management remains controversial. We present a young patient referred to our service after recent hospitalization for pneumonia. The patient was found to have a chronic effusion with a right lower lobe cystic parenchymal lesion and was taken to the operating room. The patient underwent right uniportal VATS surgery with evacuation of empyema, total pulmonary decortication, and right lower lobectomy. His postoperative course was unremarkable, and he was discharged home. Postoperative workup demonstrated lymphocyte variant hypereosinophilia. He continues to follow with thoracic surgery at the time of this report and remains asymptomatic. We conclude that uniportal VATS is a most minimally invasive, safe, and efficient approach for management of complex intrathoracic pathology including total pulmonary decortication and lobectomy.

An epigenetic switch regulates the ontogeny of AXL-positive/EGFR-TKi-resistant cells by modulating miR-335 expression.

Despite current advancements in research and therapeutics, lung cancer remains the leading cause of cancer-related mortality worldwide. This is mainly due to the resistance that patients develop against chemotherapeutic agents over the course of treatment. In the context of non-small cell lung cancers (NSCLC) harboring EGFR-oncogenic mutations, augmented levels of AXL and GAS6 have been found to drive resistance to EGFR tyrosine kinase inhibitors such as Erlotinib and Osimertinib in certain tumors with mesenchymal-like features. By studying the ontogeny of AXL-positive cells, we have identified a novel non-genetic mechanism of drug resistance based on cell-state transition. We demonstrate that AXL-positive cells are already present as a subpopulation of cancer cells in Erlotinib-naïve tumors and tumor-derived cell lines and that the expression of AXL is regulated through a stochastic mechanism centered on the epigenetic regulation of miR-335. The existence of a cell-intrinsic program through which AXL-positive/Erlotinib-resistant cells emerge infers the need of treating tumors harboring EGFR-oncogenic mutations upfront with combinatorial treatments targeting both AXL-negative and AXL-positive cancer cells.

Robotic-Assisted First Rib Resection: Our Experience and Review of the Literature.

Thoracic outlet syndrome (TOS) comprises a constellation of signs and symptoms that arise from neurologic and vascular compression of the brachial plexus and subclavian vasculature, respectively. Surgical decompression of the neurovascular structures is often indicated to alleviate TOS. We report here our robotic surgical approach and experience for resection of the first rib. Between July 2014 and January 2017, 17 patients who underwent robotic-assisted first rib resection at our institution were reviewed. Nine women and 8 men with a mean age of 45 ± 11 years had a robotic-assisted first rib resection; 8 for neurogenic TOS and 9 for venous TOS. There were no complications or conversion to open surgery. The mean operative time was 113.2 ± 55.3 minutes. Length of stay was a mean of 1.8 ± 1.9 days. Length of rib resected was 5.8 ± 0.5 cm. Anticoagulation for the venous TOS cohort was Xarelto, for a mean of 5.1 ± 1.8 months. Short-term follow-up (mean 10.3 ± 4.9 days) revealed resolution of symptoms in all patients, with patent vasculature on venogram for the entire venous TOS cohort. Further follow-up at 2 months and 6 months revealed that all patients remained symptom free. Based on our institution's experience with the robotic-assisted approach to first rib resection, we feel that it is a feasible approach that could be added to the armamentarium of the thoracic surgeon.