Interests and Barriers to Medical Students Participation in a Dedicated Global Surgery Curriculum.

INTRODUCTION: Despite many institutions establishing global surgery (GS) programs to support clinical care and education in resource-limited settings, few have established a specific curriculum in GS. This study's objective was to assess medical student interest in such a curriculum and prospects for future careers in GS/global health (GH), and to define the barriers to pursuing an international rotation. METHODS: We conducted an anonymous online survey of all 495 medical students at a major academic medical center in the mid-South that collected demographic data, country of origin, interest in a GS/GH elective, and barriers to pursuing a GS/GH rotation abroad. The data were analyzed using SPSS software. RESULTS: Prior international experience increased the likelihood of a student's involvement in GS/GH and more preclinical (years 1 & 2) students (90%) than clinical students. (years 3 & 4) (70%) felt strongly about the value of a GS/GH experience. Of the 163 students who completed the survey, 80% expressed interest in a GS/GH elective, with preclinical students expressing more interest (90%) than clinical students (71%). This interest strongly correlated with an interest in pursuing a career in GH (94%) and/or GS (100%). Identified barriers to engagement in a GS/GH experience abroad included financing (74%), scheduling (58%), family obligations (23%), and personal safety (19%). CONCLUSIONS: The students we surveyed were very interested in a GS/GH curriculum that included a rotation abroad, especially if they were to receive financial support. Preclinical students expressed more willingness to self-fund such experiences. The findings of this survey further strengthen the need to incorporate GS/GH in medical school curricula.

Macrovascular Lesions Underlying Spontaneous Intracerebral Hemorrhage.

Spontaneous intracerebral hemorrhage (ICH) is a morbid disease with a high case fatality rate. Prognosis, rehemorrhage rates, and acute, clinical decision making are greatly affected by the underlying etiology of hemorrhage. This review focuses on the evaluation, diagnosis, and management of structural, macrovascular lesions presenting with ICH, including ruptured aneurysms, brain arteriovenous malformations, cranial dural arteriovenous fistulas, and cerebral cavernous malformations.

Chemotherapy-associated pneumoperitoneum in cancer patients: a scoping review.

Background: The presence of air in the peritoneal cavity (pneumoperitoneum) is often secondary to perforated viscus. Emergent operative intervention is typically warranted in non-cancer patients. Cancer patients present a unique challenge as they have an increased risk of pneumoperitoneum due to local tumour invasion, radiation therapy, and frequent endoscopic procedures. There is a paucity of literature on the management of patients undergoing chemotherapy who present with pneumoperitoneum. The authors conducted a scoping review to identify and synthesize preliminary evidence on the presentation, management, and outcomes of this patient population. Materials and methods: A scoping review of cases of pneumoperitoneum in cancer patients from 1990 to 2022 was conducted using the Arksey and O'Malley five-stage approach. Inclusion criteria were a known diagnosis of cancer, chemotherapy within 6 months of presentation, and imaging confirmation of pneumoperitoneum. The authors' exclusion criteria were cancer diagnosis at the time of presentation, perforation secondary to local cancer invasion, and last chemotherapy session greater than 6 months prior to presentation. Results: Thirty-four cases (8 paediatric, 26 adults) were identified. The median time from the last chemotherapy treatment to presentation with pneumoperitoneum was 14 days. Twenty-one patients were managed operatively, and 13 were managed non-operatively. The most common source of perforation was multiple sites along the bowel. Thirty-day mortality was 33.3% for the operative cohort and 23.1% for the non-operative group. Conclusions: Pneumoperitoneum in cancer patients remains a highly morbid condition with a mortality rate of approximately 30%, regardless of the treatment approach. Non-operative management should be pursued whenever possible.

Management and outcomes of chemotherapy-associated pneumoperitoneum in cancer patients: a scoping review protocol.

Introduction: Pneumoperitoneum - free air within the peritoneal cavity - is often the result of bowel perforation, though other causes include residual postprocedural or postoperative air and barotrauma. In non-cancer patients, operative intervention is often required. Cancer patients, on the other hand, present a unique set of challenges as they usually have elevated risk of pneumoperitoneum from local radiation therapy, frequent endoscopic procedures, and tumor invasion. Factors such as malnutrition, neutropenia, chemotherapy, and steroid use make emergent surgery tenuous in cancer patients. There is a paucity of published literature on the management of pneumoperitoneum in patients actively undergoing chemotherapy. The main objective of this scoping review is to assess the presentation, management, and subsequent outcomes of this unique patient population. Materials and Methods: The authors will utilize the framework for performing scoping reviews as outlined by Arksey and O'Malley. They will perform the search for articles in three electronic databases (i.e. SCOPUS, PubMed, Embase) and relevant gray literature. Only articles available in English and published between 1999 and 2022 will be included. Inclusion criteria will be a known diagnosis of cancer, chemotherapy within 6 months of presentation, and imaging confirmation of pneumoperitoneum. Exclusion criteria will be cancer diagnosis at the time of presentation, perforation secondary to cancer itself, and chemotherapy greater than 6 months prior to presentation. A tailored extraction frame to extract relevant information from published articles that meet our inclusion criteria. The data using both descriptive statistics and thematic analysis of the main study questions. Ethics and Dissemination: Since the authors will not be collecting primary data, formal ethical approval is not required. They study findings will be disseminated through abstracts, conference presentations, and peer-reviewed publications.

The role of imaging and sentinel lymph node biopsy in patients with T3b-T4b melanoma with clinically negative disease.

Background: Previous studies demonstrate minimal utility of pre-operative imaging for low-risk melanoma; however, imaging may be more critical for patients with high-risk disease. Our study evaluates the impact of peri-operative cross-sectional imaging in patients with T3b-T4b melanoma. Methods: Patients with T3b-T4b melanoma who underwent wide local excision were identified from a single institution (1/1/2005 - 12/31/2020). Cross-sectional imaging was defined as body CT, PET and/or MRI in the perioperative period, with the following findings: in-transit or nodal disease, metastatic disease, incidental cancer, or other. Propensity scores were created for the odds of undergoing pre-operative imaging. Recurrence free survival was analyzed using the Kaplan-Meier method and log-rank test. Results: A total of 209 patients were identified with a median age of 65 (IQR 54-76), of which the majority were male (65.1%), with nodular melanoma (39.7%) and T4b disease (47.9%). Overall, 55.0% underwent pre-operative imaging. There were no differences in imaging findings between the pre- and post-operative cohorts. After propensity-score matching, there was no difference in recurrence free survival. Sentinel node biopsy was performed in 77.5% patients, with 47.5% resulting in a positive result. Conclusion: Pre-operative cross-sectional imaging does not impact the management of patients with high-risk melanoma. Careful consideration of imaging use is critical in the management of these patients and highlights the importance of sentinel node biopsy for stratification and decision making.

Alectinib-associated pneumoperitoneum in stage IV non-small cell lung cancer - A case report.

Introduction and importance: Alectinib, a highly potent, highly selective, brain-penetrant anaplastic lymphoma kinase (ALK) inhibitor is now the first line therapy for patients with metastatic ALK-positive non small cell lung cancer (NSCLC). Case presentation: We report a rare case of pneumoperitoneum following alectinib initiation for metastatic non small cell lung cancer in a 74-year-old African American female. Patient developed abdominal pain approximately 2 weeks after starting alectinib. She was hemodynamically stable, and imaging revealed pneumoperitoneum. Patient was successfully managed non-operatively. Clinical discussion: Gastrointestinal perforation presenting as pneumoperitoneum is a very rare complication of alectinib. To our knowledge our patient is only the second case to be reported in the literature since its approval. The complication is likely attributable to the rapid tumor regression in the gastrointestinal tract. Non-operative management should be attempted if possible. Conclusion: Oncologists should be aware of the risk of gastrointestinal perforation when initiating cytotoxic chemotherapy on patients with metastatic NSCLC. A multidisciplinary approach is critical in appropriately individualizing care in this patient population.

Methods of Sentinel Lymph Node Identification in Auricular Melanoma.

Sentinel lymph node biopsy is used to evaluate for micrometastasis in auricular melanoma. However, lymphatic drainage patterns of the ear are not well defined and predicting the location of sentinel nodes can be difficult. The goal of this study was to define the lymphatic drainage patterns of the ear and to compare multiple modalities of sentinel node identification. METHODS: A retrospective review of a prospectively maintained database evaluated 80 patients with auricular melanoma who underwent sentinel lymph node biopsy by comparing preoperative imaging with intraoperative identification of sentinel nodes. Patients were placed into two cohorts, based on the modality of preoperative imaging: (1) planar lymphoscintigraphy only (n = 63) and (2) single-photon emission computerized tomography combined with computerized tomography (SPECT-CT) only (n = 17). Sites of preoperative mapping and sites of intraoperative identification were recorded as parotid/preauricular, mastoid/postauricular, and/or cervical. RESULTS: In patients that underwent planar lymphoscintigraphy preoperatively (n = 63), significantly more sentinel nodes were identified intraoperatively than were mapped preoperatively in both the parotid/preauricular (P = 0.0017) and mastoid/postauricular (P = 0.0047) regions. Thirty-two nodes were identified intraoperatively that were not mapped preoperatively in the planar lymphoscintigraphy group (n = 63), two of which were positive for micrometastatic disease. In contrast, there were no discrepancies between preoperative mapping and intraoperative identification of sentinel nodes in the SPECT-CT group (n = 17). CONCLUSIONS: SPECT-CT is more accurate than planar lymphoscintigraphy for the preoperative identification of draining sentinel lymph nodes in auricular melanoma. If SPECT-CT is not available, planar lymphoscintigraphy can also be used safely, but careful intraoperative evaluation, even in basins not mapped by lymphoscintigraphy, must be performed to avoid missed sentinel nodes.

Hydrogel-based 3D bioprints repair rat small intestine injuries and integrate into native intestinal tissue.

3D Printing has become a mainstay of industry, with several applications in the medical field. One area that could benefit from 3D printing is intestinal failure due to injury or genetic malformations. We bioprinted cylindrical tubes from rat vascular cells that were sized to form biopatches. 2 mm enterotomies were made in the small intestine of male Sprague-Dawley rats, and sealed with biopatches. These intestinal segments were connected to an ex vivo perfusion device that provided independent extraluminal and intraluminal perfusion. The fluorescence signal of fluorescein isothiocyanate (FITC)-inulin in the intraluminal perfusate, a non-absorbable fluorescent marker of intestinal integrity, was measured every 15 min over 90 min, and used to assess the integrity of the segments under both continuous perfusion and alternate-flow perfusion. Enterotomies were made an inch away from the ileocecal junction in male Wistar rats and sealed with biopatches. The animals were monitored daily and euthanized at post-operative days 7, 14, 21, and 30. Blinded histopathological analysis was conducted to compare the patch segments to native intestine. Biopatch-sealed intestinal segments withstood both continuous and pulsatile flow rates without leakage of FITC-inulin above the control baseline. 21 of 26 animals survived with normal activity, weight gain, and stool output. Histopathology of the explanted segments showed progressive villi and crypt formation over the enterotomies, with complete restoration of the epithelium by 30 days. This study presents a novel application of 3D bioprinting to develop a universal repair patch that can seal lesions in vivo, and fully integrate into the native intestine.

Human Small Intestine Transplantation: Segmental Susceptibility to Ischemia Using Different Preservation Solutions and Conditions.

BACKGROUND AND AIMS: Among all transplanted abdominal organs, the small intestine is one of the most ischemia sensitive. Appropriate graft selection, procurement, and preservation are crucial for optimum graft and patient survival. We evaluated ischemic damage in human small intestine grafts under different hypothermic preservation conditions (cold static and continuous perfusion) and solutions: histidine-tryptophan-ketoglutarate (HTK) and University of Wisconsin (UW). METHODS: Fourteen small intestinal grafts were procured from deceased donors. HTK and UW were used for the vascular perfusion at the cross clamp, and UW, HTK, or Ringer Lactate were used for the luminal flush at the back table. Therefore, part of the same harvested intestine was stored in cold static storage and in continuous perfusion preservation (with intestinal perfusion unit) simultaneously. Histological samples were collected from the jejunum and ileum at different time points and different preservation conditions. The samples were collected before the initiation of cold storage (T0), after 8 hours of cold static (ST8), or after 8 hours of continuous perfusion preservation (PT8) (n = 161 samples). Blinded histological evaluation was conducted and ischemic damage was determined using the Park/Chiu scale. RESULTS: The ileum had less ischemic damage than the jejunum, regardless of using static or continuous perfusion preservation. There was no significantly ischemic damage difference between intestinal grafts flushed and perfused with UW or HTK. CONCLUSION: The jejunum is more susceptible to ischemic injury than the ileum. UW and HTK are equivalent to preserve intestinal graft. This suggests that selective transplantation of ileum could reduce ischemia-related postoperative complications.

Activation of the Calcium Sensing Receptor Decreases Secretagogue-Induced Fluid Secretion in the Rat Small Intestine.

BACKGROUND: The calcium-sensing receptor (CaSR) has been localized and characterized in numerous tissues throughout the body. In the mammalian gastrointestinal tract, the CaSR is known to act as a nutrient sensor and has recently been found to play a role in intestinal fluid and electrolyte balance. This study aims to demonstrate the functionality of the CaSR as a modulator of fluid secretion and absorption along the small intestine. METHODS: Small intestine regions (proximal, middle, and distal) were isolated from Sprague Dawley rats and loaded into an ex vivo intestinal perfusion device that provides independent intraluminal and extraluminal (serosa/basolateral) perfusion. The regions were perfused with 5 and 7 mM of Ca2+, both in the presence and absence of forskolin (FSK), a potent secretagogue. Control experiments were conducted with intraluminal perfusate containing standard Ringer-HEPES buffer with a physiological concentration of Ca2+ (1 mM). A second set of comparison experiments was performed with intraluminal perfusates containing AC-265347, a CaSR activator and agonist, in the presence of FSK. In all experimental conditions, the intraluminal perfusate contained fluorescein isothiocyanate (FITC)-inulin, a nonabsorbable fluorescent marker of secretion and/or absorption. Intraluminal fluorescence signal was utilized as a measure of water movement at the start of the experiment and every 15 min for 90 min. RESULTS: Under physiological conditions, increasing the concentration of Ca2+ in the luminal perfusate reduced intestinal fluid secretion in all regions. At a Ca2+ concentration of 7 mM, net fluid absorption was observed in all regions. In the presence of FSK, 5 mM Ca2+ significantly decreased fluid secretion and 7 mM Ca2+ abolished FSK-induced fluid secretion. Intraluminal perfusion with 5 mM Ca2+ was as effective as AC-265347, in reducing secretagogue-induced fluid hypersecretion in the proximal and middle regions. CONCLUSION: This study concludes that apical CaSR is active along the small intestine. Its activation by Ca2+ and/or calcimimetics reduces fluid secretion in a dose-dependent manner, with higher Ca2+ concentrations, or application of a calcimimetic, leading to fluid absorption. We furthermore show that, in the presence of FSK, receptor activation abates FSK secretagogue-induced fluid secretion. This presents a new therapeutic target to address secretory diarrheal illnesses.

Generating vascular conduits: from tissue engineering to three-dimensional bioprinting.

Vascular disease - including coronary artery disease, carotid artery disease, and peripheral vascular disease - is a leading cause of morbidity and mortality worldwide. The standard of care for restoring patency or bypassing occluded vessels involves using autologous grafts, typically the saphenous veins or internal mammary arteries. Yet, many patients who need life- or limb-saving procedures have poor outcomes, and a third of patients who need vascular intervention have multivessel disease and therefore lack appropriate vasculature to harvest autologous grafts from. Given the steady increase in the prevalence of vascular disease, there is great need for grafts with the biological and mechanical properties of native vessels that can be used as vascular conduits. In this review, we present an overview of methods that have been employed to generate suitable vascular conduits, focusing on the advances in tissue engineering methods and current three-dimensional (3D) bioprinting methods. Tissue-engineered vascular grafts have been fabricated using a variety of approaches such as using preexisting scaffolds and acellular organic compounds. We also give an extensive overview of the novel use of 3D bioprinting as means of generating new vascular conduits. Different strategies have been employed in bioprinting, and the use of cell-based inks to create de novo structures offers a promising solution to bridge the gap of paucity of optimal donor grafts. Lastly, we provide a glimpse of our work to create scaffold-free, bioreactor-free, 3D bioprinted vessels from a combination of rat vascular smooth muscle cells and fibroblasts that remain patent and retain the tensile and mechanical strength of native vessels.