Predicting response to neoadjuvant chemotherapy for colorectal liver metastasis using deep learning on prechemotherapy cross-sectional imaging.

BACKGROUND AND OBJECTIVES: Deep learning models (DLMs) are applied across domains of health sciences to generate meaningful predictions. DLMs make use of neural networks to generate predictions from discrete data inputs. This study employs DLM on prechemotherapy cross-sectional imaging to predict patients' response to neoadjuvant chemotherapy. METHODS: Adult patients with colorectal liver metastasis who underwent surgery after neoadjuvant chemotherapy were included. A DLM was trained on computed tomography images using attention-based multiple-instance learning. A logistic regression model incorporating clinical parameters of the Fong clinical risk score was used for comparison. Both model performances were benchmarked against the Response Evaluation Criteria in Solid Tumors criteria. A receiver operating curve was created and resulting area under the curve (AUC) was determined. RESULTS: Ninety-five patients were included, with 33,619 images available for study inclusion. Ninety-five percent of patients underwent 5-fluorouracil-based chemotherapy with oxaliplatin and/or irinotecan. Sixty percent of the patients were categorized as chemotherapy responders (30% reduction in tumor diameter). The DLM had an AUC of 0.77. The AUC for the clinical model was 0.41. CONCLUSIONS: Image-based DLM for prediction of response to neoadjuvant chemotherapy in patients with colorectal cancer liver metastases was superior to a clinical-based model. These results demonstrate potential to identify nonresponders to chemotherapy and guide select patients toward earlier curative resection.

Manufacturing of a Human Adipose-Derived Hydrogel.

Hydrogels are considered a viable in vitro alternative to monolayer cultures. They provide quintessential characteristics for in vitro studies including biocompatibility, biodegradability, viscoelasticity, hydrophilicity, and low toxicity. Furthermore, many provide necessary extracellular matrix proteins and architecture to support cell growth, proliferation, differentiation, and migration. Synthetic and natural polymer-derived hydrogels both demonstrate positive qualities; however, natural hydrogels have attracted great interest due to their clinical relevancy. In particular, decellularized tissue-derived hydrogels have been identified as a significant resource for tissue engineering applications by mimicking the composition and architecture of their tissue of origin.The use of adipose tissue as a hydrogel has become more prevalent because of limitless resources and accessibility of the tissue itself. Obatala Sciences has established a manufacturing protocol for human decellularized adipose tissue (hDAT) using a series of steps including mechanical disruption, chemical disruption with N-Lauroylsarcosine, and enzymatic digestion with pepsin and hydrochloric acid.

Quality Control Assessment of Human Adipose-Derived Hydrogels.

Decellularized human-adipose tissue (hDAT) can serve as an alternative to two-dimensional monolayer culture and current ECM hydrogels due to its unlimited availability and cytocompatibility. A major hurdle in the clinical translation and integration of hDAT and other hydrogels into current in vitro culture processes is adherence to current good manufacturing practices (cGMP). Transferring of innovative technologies, including hydrogels, requires the establishing standardized protocols for quality assurance and quality control (QA/QC) of the material.Integration of basic characterization techniques, including physiochemical characterization, structural/morphological characterization, thermal and mechanical characterization, and biological characterization, in addition to the reduction of batch-to-batch variability and establishment of proper sterilization, storage, and fabrication processes verifies the integrity of the hydrogel. Obatala Sciences has established a characterization protocol that involves a series of assays including the evaluation of gelation properties, protein content, glycosaminoglycan content, soluble collagen content, and DNA content of hDAT.

Biomechanical and Biological Characterization of XGel, a Human-Derived Hydrogel for Stem Cell Expansion and Tissue Engineering.

Hydrogels are 3D scaffolds used as alternatives to in vivo models for disease modeling and delivery of cells and drugs. Existing hydrogel classifications include synthetic, recombinant, chemically defined, plant- or animal-based, and tissue-derived matrices. There is a need for materials that can support both human tissue modeling and clinically relevant applications requiring stiffness tunability. Human-derived hydrogels are not only clinically relevant, but they also minimize the use of animal models for pre-clinical studies. This study aims to characterize XGel, a new human-derived hydrogel as an alternative to current murine-derived and synthetic recombinant hydrogels that features unique physiochemical, biochemical, and biological properties that support adipocyte and bone differentiation. Rheology studies determine the viscosity, stiffness, and gelation features of XGel. Quantitative studies for quality control support consistency in the protein content between lots. Proteomics studies reveal that XGel is predominantly composed of extracellular matrix proteins, including fibrillin, collagens I-VI, and fibronectin. Electron microscopy of the hydrogel provides phenotypic characteristics in terms of porosity and fiber size. The hydrogel demonstrates biocompatibility as a coating material and as a 3D scaffold for the growth of multiple cell types. The results provide insight into the biological compatibility of this human-derived hydrogel for tissue engineering.

African American Patients Experience Worse Outcomes than Hispanic Patients Following Bariatric Surgery: an Analysis Using the MBSAQIP Data Registry.

BACKGROUND: Obesity rates in Hispanics and African Americans (AAs) are higher than in Caucasians in the USA, yet the rate of metabolic and bariatric surgery (MBS) for weight loss remains lower for both Hispanics and AAs. METHODS: Patient demographics and outcomes of adult AA and Hispanic patients undergoing sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) procedures were analyzed using the MBSAQIP dataset [2015-2018] using unmatched and propensity-matched data. RESULTS: In total, 173,157 patients were included, of whom 98,185 were AA [56.7%] [21,163-RYGB; 77,022-SG] and 74,972 were Hispanic [43.3%] [20,282-RYGB; 54,690-SG]). Preoperatively, the AA cohort was older, had more females, and higher BMIs with higher rates of all tracked obesity-related medical conditions except for diabetes, venous stasis, and prior foregut surgery. Intra- and postoperatively, AAs were more likely to experience major complications including unplanned ICU admission, 30-day readmission/reintervention, and mortality. After propensity matching, the differences in ED visits, treatment for dehydration, 30-day readmission, 30-day intervention, and pulmonary embolism remained for both SG and RYGB cohorts. Progressive renal insufficiency and ventilator use lost statistical significance in both cohorts. Conversely, 30-day reoperation, postoperative ventilator requirement, unplanned intubation, unplanned ICU admission, and mortality lost significance in the RYGB cohort, but not SG patients. CONCLUSION: Outcomes for AA patients were worse than for Hispanic patients, even after propensity matching. After matching, differences in major complications and mortality lost significance for RYGB, but not SG. These data suggest that outcomes for RYGB may be driven by the presence and severity of pre-existing patient-related factors.

Enhanced Recovery After Surgery® in Octogenarians Undergoing Hepatopancreatobiliary Surgery.

Advances in perioperative care have increased the frequency of surgical intervention performed on the very elderly (≥80 years). This study aims to investigate the impact of Enhanced Recovery After Surgery (ERAS) on outcomes for octogenarians after major hepatopancreatobiliary (HPB) surgery. Patients ≥80 years old in a single HPB ERAS program (September 2015-July 2018) were prospectively tracked in the ERAS Interactive Audit System (EIAS). Postoperative length of stay (LOS) as well as 30-day major complications, readmissions, and mortality were compared to a pre-ERAS octogenarian control. Since ERAS implementation, octogenarians comprised 7.3% (27 of 370) of patients who underwent pancreaticoduodenectomy (n=17), distal pancreatectomy (n=7), or hepatectomy (n=3). Thirty-day readmissions decreased after ERAS implementation (50% to 15%, P=.037). Thirty-day major complications, mortality, and LOS were similar with 64% median protocol compliance. ERAS for octogenarians in HPB surgery is safe and may contribute to more sustainable recovery resulting in reduced readmissions.

Robotic Resection of Gallbladder Cancer: A Single-Center Retrospective Comparative Study to Open Resection.

BACKGROUND: Minimally invasive surgery is gaining support for resection of gallbladder cancer (GBC). This study aims to compare operative and early outcomes of robotic resection (RR) to open resection (OR) from a single institution performing a high volume of robotic HPB surgery. METHODS: Twenty patients with GBC underwent RR from January 2013 to August 2019. Outcomes were compared to a historical control of 23 patients with OR. Radical cholecystectomy for suspected GBC and completion operations for incidental GBC after routine cholecystectomy were both included. RESULTS: Robotic resection had lower blood loss compared to OR (150 vs 350 mL, P = .002) and shorter postoperative length of stay (2.5 vs 6 days, P < .001), while median operative time was similar (193 vs 208 min, P = .604). There were no statistical differences in 30-day major complications or readmissions. No 30-day mortalities occurred. There was no statistical difference in survival trend (P = .438) or median lymph node harvest (5 vs 3, P = .189) for RR compared to OR. CONCLUSION: Robotic resection of GBC is safe and efficient, with lower length of hospital stay and blood loss compared to OR. Technical benefits of robotic-assisted surgery may prove advantageous though larger studies are still needed.

Intercostal Lung Hernia Following Deep Inferior Epigastric Perforator Reconstruction.

Acquired lung hernias typically result from trauma or intra-thoracic surgery is defined as the protrusion of lung parenchyma beyond the anatomic boundaries of the thoracic wall. A 40-year-old woman underwent deep inferior epigastric perforator (DIEP) breast reconstruction following her mastectomies. Post-operatively, she returned to the emergency department with severe chest pain, shortness of breath, and localized chest swelling. CT angiography demonstrated intercostal right lung hernia with concern for incarceration. She returned emergently to the operating room. The lung was reduced, but the flap was ultimately determined to be nonviable and was removed. Post-operative course was uneventful and the patient recovered well. Intercostal lung hernia is an uncommon clinical entity that has not previously been described as a complication of DIEP breast reconstruction. Its development is associated with significant morbidity including flap loss in this case. Early recognition of this rare complication is essential to avoid more severe sequelae of tissue ischemia.

Robotic Revision of Hepaticojejunostomy for Benign Biliary Stricture.

Surgical revision of biliary enteric anastomoses (BEA) can be a challenging undertaking and a robotic platform may provide advantages that address many of the technical obstacles. We present our technical approach and outcomes for patients undergoing robotic revision of BEA for benign strictures. A retrospective review was performed for robot-assisted benign BEA revision at our institution. Operative details, perioperative metrics, and outcomes are reported. Four patients underwent anastomotic revision following previously failed non-operative management. There were no intraoperative complications, mean length of stay was 4-days, and all patients experienced resolution of presenting clinical signs and symptoms. No patients required reoperation and there was no mortality. Postoperative outcomes were consistent with findings reported for other interventional modalities. Based on our experience we conclude robotic intervention in this context is safe and improves the technical feasibility of this complex procedure.

Atrial Cannulation During Resuscitative Clamshell Thoracotomy.

BACKGROUND: Resuscitative thoracotomy and clamshell thoracotomy are performed in the setting of traumatic arrest with the intent of controlling hemorrhage, relieving tamponade, and providing open chest cardiopulmonary resuscitation. Historically, return of spontaneous circulation rates for penetrating traumatic arrest as well as out of hospital survival have been reported as low as 40% and 10%. Vascular access can be challenging in patients who have undergone a traumatic arrest and can be a limiting step to effective resuscitation. Atrial cannulation is a well-established surgical technique in cardiac surgery. Herein, we present a case series detailing our application of this technique in the context of acute trauma resuscitation during clamshell thoracotomy for traumatic arrest in the emergency department. METHODS: A retrospective case series of atrial cannulation during traumatic arrest was conducted in Charlotte, NC at Carolinas Medical Center an urban level 1 trauma center. RESULTS: The mean rate of return of spontaneous circulation in our series, 60%, was greater than previously published upper limit of return of spontaneous circulation for penetrating causes of traumatic arrest. DISCUSSION: Intravenous access can be difficult to establish in the hypovolemic and exsanguinating patient. Traditional methods of vascular access may be insufficient in the setting of central vascular injury. Atrial appendage cannulation during atrial cannulation is a quick and reliable technique to achieve vascular access that employs common methods from cardiac surgery to improve resuscitation of traumatic arrest.

The "Frogger Flap": A Novel Quadruple Rhomboid Flap for Complex Central Upper Lip Reconstruction.

Upper lip reconstruction represents a unique challenge for the reconstructive plastic surgeon. Given its prominent aesthetic role in addition to its functional role in facial expression, speech, and oral intake, preservation of this region's natural form and function is paramount. In this report, we present a novel technique for the reconstruction of a complex central upper lip defect, restoring the natural aesthetic of this essential structure. We describe the case of a 51-year-old woman who presented with recurrence of a previously resected basal cell carcinoma center on the upper lip at the level of the white roll and philtral depression. Following surgical resection via Mohs micrographic surgery, a 1.8 × 1.6 cm partial-thickness defect centered around the Cupid bow involving both cutaneous and vermillion tissues remained. Reconstruction was achieved through a novel quadruple rhomboid flap primarily based on the preservation of the aesthetic subunits of the upper lip. A functional and aesthetic reconstruction was achieved through local tissue rearrangement, restoring the appearance of the white roll and red line. Native perfusion and innervation were preserved during the reconstruction of the Cupid bow, recreating this region's natural appearance. The design of the flap resembles a jumping frog, which is the etiology of the "Frogger flap" moniker. The Frogger flap recreates the natural aesthetic of the central upper lip through the geometric transposition of tissue commensurate with native anatomy. Through the application of aesthetic subunit principles, it reliably reconstructs central upper lip defects while preserving function and providing an aesthetically pleasing outcome.

Why Size Matters: an Evaluation of Gastric Pouch Size in Roux-en-Y Gastric Bypass Using CT Volumetric Analysis and its Effect on Marginal Ulceration.

PURPOSE: Marginal ulceration (MU) is a common long-term complication following Roux-en-Y gastric bypass (RYGB). The causes of MU after RYGB are multifactorial and include surgical technique of constructing the gastrojejunal anastomosis (GJA). The purpose of this study is to evaluate the relationship between gastric pouch size in RYGB and MU using CT volumetrics. MATERIAL AND METHODS: Patients were retrospectively identified who underwent esophagogastroduodenoscopy (EGD) following RYGB at a tertiary care teaching hospital. Measurement of gastric pouch size was performed using 3-D CT software. Standard statistical methods were used, a univariate comparison was performed between MU and non-MU patients followed by a propensity-matched comparison to control for factors known to affect MU, and a propensity-matched subgroup analysis was also performed. RESULTS: In total, 122 patients met criteria, 57 of which had MU on EGD and 65 who did not. The MU group had more smokers and patients with PPI use than the non-MU group, and the mean time from operation to CT scan was 26.6 months (range: 0-108 months). The MU group had a larger gastric pouch size than the non-MU group (34.1 ± 11.8 versus 20.1 ± 6.8 cm3). When analyzed for matched patient cohorts, this difference remained for the MU group that included smokers and PPI use. When stratified for pouch size, for each 5 cm3 increase in pouch size, patients had 2.4 times odds increase of MU formation. CONCLUSIONS: CT volumetric analysis demonstrated that a larger gastric pouch size was associated with MU following RYGB.

Facial Nerve Reconstruction Using Acellular Nerve Allograft.

ABSTRACT: When repaired with interposition nerve grafts, segmental facial nerve defects are traditionally treated with nerve autograft. The authors present a patient who presented after partial resection of a basal cell carcinoma over the left zygomatic region with positive deep and peripheral margins and complete loss of frontal and zygomatic facial nerve function. She was subsequently treated with wide resection, superficial parotidectomy, and cervicofacial flap. The parotidectomy was performed for deep margin control and the facial nerve was dissected distally demonstrating the prior resection of a segment of frontal and zygomatic branches consistent with clinical exam. For acute segmental facial nerve defects, nerve autograft has been the gold standard. in our patient, segmental repair using processed nerve allograft demonstrated rapid and complete recovery. This is a viable option for facial nerve reconstruction with various benefits of avoiding donor site morbidity, ease of allograft nerve handling and decreased operative time.

Long-Term Clinical Outcomes of an Antibiotic-Coated Non-Cross-linked Porcine Acellular Dermal Graft for Abdominal Wall Reconstruction for High-Risk and Contaminated Wounds.

BACKGROUND: Abdominal wall reconstruction in high-risk and contaminated cases remains a challenging surgical dilemma. We report long-term clinical outcomes for a rifampin-/minocycline-coated acellular dermal graft (XenMatrix™ AB) in complex abdominal wall reconstruction for patients with a prior open abdomen or contaminated wounds. METHODS: Patients undergoing abdominal wall reconstruction at our institution at high risk for surgical site occurrence and reconstructed with XenMatrix™ AB with intent-to-treat between 2014 and 2017 were included. Demographics, operative characteristics, and outcomes were collected. The primary outcome was hernia recurrence. The secondary outcomes included length of stay, surgical site occurrence, readmission, morbidity, and mortality. RESULTS: Twenty-two patients underwent abdominal wall reconstruction using XenMatrix™ AB during the study period. Two patients died while inpatient from progression of their comorbid diseases and were excluded. Sixty percent of patients had an open abdomen at the time of repair. All patients were from modified Ventral Hernia Working Group class 2 or 3. There were a total of four 30-day infectious complications including superficial cellulitis/fat necrosis (15%) and one intraperitoneal abscess (5%). No patients required reoperation or graft excision. Median clinical follow-up was 38.2 months with a mean of 35.2 +/- 18.5 months. Two asymptomatic recurrences and one symptomatic recurrence were noted during this period with one planning for elective repair of an eventration. Follow-up was extended by phone interview which identified no additional recurrences at a median of 45.5 and mean of 50.5 +/-12.7 months. CONCLUSION: We present long-term outcomes for patients with high-risk and contaminated wounds who underwent abdominal wall reconstruction reinforced with XenMatrix™ AB to achieve early, permanent abdominal closure. Acceptable outcomes were noted.

Smoking, Obesity, and the Elective Operation.

Smoking and obesity are commonly encountered problems in the elective, perioperative setting. This article reviews the risks posed by smoking and diabetes and explores way to mitigate such risks. Other means of perioperative optimization are also discussed in an effort to describe perioperative strategies that can improve patient outcomes.

Omental Free Flap Coverage for Extracavitary Vascular Bypass Graft Salvage.

BACKGROUND: Prosthetic vascular graft infection is a serious complication associated with significant morbidity and mortality often requiring graft excision and numerous additional operations. Pedicled flaps are often used for the coverage of exposed deep tissue or hardware for graft salvage. In the absence of pedicled options, the properties of omentum make it an excellent choice for free flap tissue coverage, particularly in cases involving implanted prostheses. METHODS: A 63-year-old woman developed a mycotic right subclavian arterial aneurysm requiring ligation and extra-anatomic bypass grafting to restore right-sided intracranial and right upper extremity arterial perfusion. Subsequent wound breakdown and poor healing left the grafts exposed, resulting in contamination. Given the profound risks associated with graft excision in this patient, salvage was attempted with IV antibiotics, serial wound/graft washouts, and graft coverage with an omental free flap. RESULTS: The patient tolerated the procedure well. The remainder of her hospital course was uneventful, and she was discharged home in good clinical condition. She will remain on long-term suppressive antibiotics per Infectious Disease recommendations. CONCLUSIONS: Contemporary literature reporting novel and effective applications of omental free flap coverage is rare. This report demonstrates that omental free flap coverage is safe and can provide healthy tissue to protect implanted grafts and even aid in the salvage of infected extra-anatomic bypass grafts.

Objective evaluation of technical dexterity in robotic hepaticojejunostomy: Assessment of hepatopancreatobiliary fellows using cumulative sum analytics.

BACKGROUND: The development of technical dexterity is a critical for surgeons in training. This study describes and assesses the feasibility of an objective method for the evaluation of procedure-specific technical dexterity in hepatopancreatobiliary (HPB) surgery using cumulative sum (CUSUM) analysis. METHODS: Dry-lab HPB procedures were divided into procedural steps with binary outcomes (success or failure). Two HPB fellows completed 20 dry lab hepaticojejunostomy (HJ) procedures. Participant progress was tracked over time with CUSUM analytics to establish a learning curve for procedural proficiency. RESULTS: The CUSUM charts for 20 consecutive dry-lab HJ procedures were analysed. A learning curve was created and used to identify areas of weakness to facilitate improvement in technical proficiency. CONCLUSIONS: CUSUM is effective tool for objective evaluation of technical dexterity offering both simplicity and adaptability. We demonstrate its use and feasibility for surgical education and plan to expand its' application to assess residents performing general surgery procedures.

Transition from Intravenous to Subcutaneous Daratumumab Formulation in Clinical Practice.

INTRODUCTION: Daratumumab is an anti-CD38 monoclonal antibody widely used for treating patients with newly diagnosed or relapsed/refractory multiple myeloma. The subcutaneous formulation of daratumumab was developed with the purpose of minimizing the treatment burden (to patients and health care system) associated with intravenous daratumumab. Given its recent approval, there is a knowledge gap regarding the best practices that should be instituted for safe administration of subcutaneous daratumumab. METHODS: A retrospective chart review was performed from August 2020 until November 2020 to identify patients either switched to or treated upfront (daratumumab naive) with any subcutaneous daratumumab-based treatment regimen. All patients received appropriate premedications per institutional standards of care. The study end points were to report real-world data regarding administration-related reaction rates (at or following discharge from infusion center), as well as compare their incidence rates to those noted in the COLUMBA study (historical cohort). RESULTS: The study included 58 patients, of whom 38% (n = 22) were daratumumab naive. The majority (84%, n = 49) received subcutaneous daratumumab in combination with various antimyeloma regimens. There were no cases of administration-related reactions at infusion center or after discharge irrespective of previous exposure to intravenous daratumumab. None of the patients included herein required rescue home medications or visited the emergency department within 24 to 48 hours after subcutaneous daratumumab administration. These translated into a significant difference in incidence of administration-related reactions compared with historical cohort (0% vs. 13%, P = .003). CONCLUSION: Subcutaneous daratumumab was extremely well tolerated and could be safely administered without need for monitoring or rescue home medications.

Adipose-derived cells: building blocks of three-dimensional microphysiological systems.

Microphysiological systems (MPS) created with human-derived cells and biomaterial scaffolds offer a potential in vitro alternative to in vivo animal models. The adoption of three-dimensional MPS models has economic, ethical, regulatory, and scientific implications for the fields of regenerative medicine, metabolism/obesity, oncology, and pharmaceutical drug discovery. Key opinion leaders acknowledge that MPS tools are uniquely positioned to aid in the objective to reduce, refine, and eventually replace animal experimentation while improving the accuracy of the finding's clinical translation. Adipose tissue has proven to be an accessible and available source of human-derived stromal vascular fraction (SVF) cells, a heterogeneous population available at point of care, and adipose-derived stromal/stem cells, a relatively homogeneous population requiring plastic adherence and culture expansion of the SVF cells. The adipose-derived stromal/stem cells or SVF cells, in combination with human tissue or synthetic biomaterial scaffolds, can be maintained for extended culture periods as three-dimensional MPS models under angiogenic, stromal, adipogenic, or osteogenic conditions. This review highlights recent literature relating to the versatile use of adipose-derived cells as fundamental components of three-dimensional MPS models for discovery research and development. In this context, it compares the merits and limitations of the adipose-derived stromal/stem cells relative to SVF cell models and considers the likely directions that this emerging field of scientific discovery will take in the near future.