Intraoperative Samples Research Articles

Abstract A074: Early detection of breast implant associated anaplastic large cell lymphoma by multiplex lateral flow assay of CD30 and IL-10

Abstract Introduction: More than 1300 women have developed a unique breast implant associated anaplastic large cell lymphoma (BIA-ALCL) around breast implants. BIA-ALCL presents as an accumulation of fluid (seroma) a median of 9 years after implant placement. When detected early, survival with surgery alone is nearly 100%. Remaining patients present with masses and/or lymph node metastases requiring radiation, chemotherapy and/or immunotherapy and fatalities have occurred. Methods: Preliminary studies identified CD30 and IL-10 as the most sensitive and specific biomarkers for BIA-ALCL in seroma fluids. Therefore, we constructed a multiplex LFA to detect both CD30 and IL-10 in 30 mL seroma fluid within 20 minutes. LFA is a point of care immunoassay using capture and detection antibodies that detect separate epitopes of the target molecule. The detection antibody is linked to a colored particle; in this multiplex assay CD30 antibody was linked to blue and IL-10 to red particles. Separate positive test lines (blue and red) indicate presence of CD30 or IL-10. A control line confirms migration of the seroma fluid past the test lines. To determine the dynamic range of sensitivity we spiked recombinant CD30 and IL-10 into benign seromas. Test and control lines were quantitated with NIH Image J software and ratios of test line to control line calculate for each sample. Forty-eight hour supernatants of supernatants of BIA-ALCL lines TLBR1 and TLBR2 were tested for IL-10 and CD30. Fifteen patients, 8 with BIA-ALCL and 7 with benign seromas provided consent for testing of their seroma fluids. Results: Multiplex CD30/IL10 LFA produced positive test lines for neat and 1:10 dilutions of 48 hour supernatnats of BIA-ALCL lines TLBR1 and TLBR2. Both IL-10 and CD-30 could be detected on the multiplex LFA strip using a 1:3 dilution of seroma fluids. The multiplex LFA shows both IL-10 and CD30 are significantly higher in malignant samples (IL-10 TL/CL: malignant, 0.2±0.16 n=8 vs benign, 0.004±0.007 n=7, p<0.05; CD30 TL/CL: malignant, 0.38±0.2 vs benign, 0.02±0.02, p<0.001, two-way ANOVA). Importantly, when either IL-10 or CD30 yields a faint positive test line, the other is not detected reducing the possibility of false positives. Conclusions: The CD30/IL-10 multiplex LFA had 100% positive and negative predictive value in this pilot study. The assay was able to distinguish lymphoma from recurrent breast cancer and more common benign seromas. The use of this multiplex assay mitigates positive false positive results from more sensitive CD30 LFA which has been detected in some benign seromas. This LFA will potentially allow early pre-operative detection of ALCL allowing surgeons to plan their surgical approach. The LFA can replace more costly time-consuming flow cytometry, immunohistochemistry, cyto- and histopathologic studies which require at least 10 ml of fluid. The LFA can be performed outside of medical centers in rural and underserved areas. A larger prospective multicenter study including intra-operative sampling is planned to validate these results. Citation Format: Peng Xu, Katerina Kourentzi, Richard Willson, Marshall Kadin. Early detection of breast implant associated anaplastic large cell lymphoma by multiplex lateral flow assay of CD30 and IL-10 [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr A074.

Musculoskeletal Tumor Society Member Survey: Intra-Operative Peripheral Margins in Soft Tissue Sarcoma.

Routine intraoperative peripheral margin sampling is often employed by musculoskeletal surgical oncologists. Several recommendations exist regarding this practice pattern. It is unknown what the practice patterns of Musculoskeletal Tumor Society (MSTS) members are. Evidence-based data to support or refute this practice is currently lacking. We developed an anonymous survey with two primary objectives. To determine the practice patterns of active MSTS members with respect to intraoperative peripheral margin sampling and to elucidate the most common rationale for routine sampling. An anonymous survey was distributed through the MSTS to 320 active members. Results were collected with a branching logic fashion via Microsoft Forms®. Surveys were sent to 320 MSTS members in 2021. A total of 108 responses were collected. A total of 55 (51%) respondents noted that they routinely send intraoperative peripheral margins. Primary reasons for margin assessment included concerns about adequacy of margins. Members who routinely send frozen margins sent on average 4-6 specimens. There is significant variability in this practice amongst MSTS members. Given there is no evidence to support or refute this practice, Further investigation is required to determine the clinical utility of routine intraoperative peripheral margin sampling.

TMET-02. CELL-INTRINSIC METABOLIC PHENOTYPES IDENTIFIED IN GLIOBLASTOMA PATIENTS USING MASS SPECTROMETRY IMAGING OF 13C-LABELED GLUCOSE METABOLISM

Abstract Glioblastoma (GB) is an inherently heterogeneous and invasive primary brain cancer. Genomic and transcriptomic studies have attempted to classify GB into subtypes that predict survival and that have different therapeutic vulnerabilities. An outstanding question and technical challenge is to visualize the metabolism of a tumour within its native microenvironment and understand to what extent its metabolism is driven by the microenvironment. Patients with GB tumours were infused with [U-13C]glucose and intra-operative multi-regional tumour samples were rapidly snap frozen for analysis using mass spectrometry imaging (MSI). Tissue microenvironment was assessed using multiplexed antibodies in immunocytochemistry (IMC) of contiguous sections. Isotope tracking in human-derived neurospheres and patient-derived xenografts were used to confirm the presence of metabolic phenotypes detected in the human samples and to test the susceptibility of each phenotype to a panel of drugs targeting cellular metabolism. Three metabolic signatures were identified in patient tumours: glycolytic, oxidative and a mixed glycolytic/oxidative phenotype. The phenotypes did not correlate with microenvironmental features, including proliferation rate, immune cell infiltration, and vascularisation. The phenotypes were retained when patient-derived cells were grown in vitro, or as orthotopically implanted xenografts, and were robust to changes in oxygen concentration, demonstrating their cell intrinsic nature. The spatial extent of the regions occupied by cells displaying these distinct metabolic phenotypes are large enough to be detected using clinically applicable metabolic imaging techniques. The phenotypes also demonstrate differential drug sensitivities, suggesting imaging of these phenotypes may be used to stratify patients for personalised therapy trials. This is the first report to demonstrate high resolution imaging of metabolic fluxes in a human tumour in vivo and the presence of different metabolic phenotypes within GB that are tumour cell intrinsic and largely independent of the tumour microenvironment.

Intraoperative Peripheral Frozen Margin Assessment in Soft Tissue Sarcoma.

Intraoperative peripheral margin sampling in soft tissue sarcoma (STS) is a routine practice among musculoskeletal oncologists. Practice patterns are variable, and evidence to support it is lacking. Rates of peripheral margin sampling at our institution were analyzed in addition to its clinical utility and cost-effectiveness. Peripheral margin sampling patterns at a tertiary sarcoma center were retrospectively evaluated. Concordance between peripheral margins and final pathology was assessed using McNemar's test and κ Coefficient. Clinical outcomes were compared, and a cost-utility analysis was performed. A total of 179 patients were included. 66% had peripheral margins sampled of which 23% had frozen margins analyzed. Ten patients had positive margins (5.5% of all patients; 8.4% in those with margins sampled) and R1 margins on the final tumor specimen were identified in 15 patients (8.4%). There were no R2 resections. Three patients underwent repeat surgical resection (20%). Three patients with R1 resections had negative peripheral margins sampled, suggesting falsely reassuring peripheral margins. Peripheral margin sampling averaged $5000/patient. Routine peripheral margin sampling in STS resection is of questionable utility with added cost. Prospective studies are warranted to determine the optimal approach to surgical margin assessment.

BIOM-33. INVESTIGATING MIR-21 AS A NON-INVASIVE PROGNOSTIC BIOMARKER IN GLIOMA PATIENTS IN RESOURCE CONSTRAINT SETTINGS

Abstract BACKGROUND Glioma treatment remains challenging due to high recurrence rates and resistance to treatment. Diagnosis and follow-up in resource-constrained regions often leads to significant patient attrition. Serum microRNA (miRNA) expression profiles are shown to be expressed in tumor tissue and peripheral samples, offering a pathway for non-invasive, repetitive liquid biopsies. miR-21 shows promise in many populations; however, there is a dearth of data from our region. METHODOLOGY we collected 89 intraoperative tumor tissue samples, 42 pre- and post-operative serum samples from glioma patients, and included 10 control tissue samples along with 8 normal serum samples and analyzed for miR-21 expression through qPCR. Serum samples were collected before tumor resection and post-surgery (pre- and post-operative). Correlational analysis with molecular markers IDH, Ki-67, ATRX, p53, and survival curves through the Kaplan-Meier method were calculated in high and low miR-21 expression groups, The hazard ratio was quantitatively determined using Cox regression analysis, considering both univariate associations and multivariate correlations with clinical parameters. RESULTS miR-21 expression in tissue increased with higher grades of glioma (p=0.00064), of patients above 50 years (p=0.0027), and shows a positive correlation with tumor volume (r= 0.22, p=0.081). IDH-wildtype (p=2.06e-03) and high Ki-67 (p=2.50e-03) expression in tumors showed significant upregulation of miR-21 compared to IDH-mutant and low Ki-67. Patients with low miR-21 expression had significantly longer overall survival (OS) than patients with high miR-21 expression (p =0.006). Quantitative hazard analysis indicates that patients in the high expression group have a 2.77 times higher risk of mortality (95% CI: upper - 0.19, lower - 0.92), in comparison to patients in the low expression group (p= 0.008). CONCLUSION Our findings validate the future utility of miR-21 as a serum assay to help diagnose and assess treatment response in different grades of glioma, within our population. Keywords: Glioma, Biomarker, Molecular markers, Liquid biopsy

Blood and Bone-Derived DNA Methylation Ages Predict Mortality After Geriatric Hip Fracture: A Pilot Study.

The purpose of this study was to (1) perform the first analysis of bone-derived DNA methylation, (2) compare DNA methylation clocks derived from bone with those derived from whole blood, and (3) establish a relationship between DNA methylation age and 1-year mortality within the geriatric hip fracture population. Patients ≥65 years old who presented to a Level-I trauma center with a hip fracture were prospectively enrolled from 2020 to 2021. Preoperative whole blood and intraoperative bone samples were collected. Following DNA extraction, RRBS (reduced representation bisulfite sequencing) libraries for methylation clock analysis were prepared. Sequencing data were analyzed using computational algorithms previously described by Horvath et al. to build a regression model of methylation (biological) age for each tissue type. Student t tests were used to analyze differences (Δ) in methylation age versus chronological age. Correlation between blood and bone methylation ages was expressed using the Pearson R coefficient. Blood and bone samples were collected from 47 patients. DNA extraction, sequencing, and methylation analysis were performed on 24 specimens from 12 subjects. Mean age at presentation was 85.4 ± 8.65 years. There was no difference in DNA extraction yield between the blood and bone samples (p = 0.935). The mean follow-up duration was 12.4 ± 4.3 months. The mortality cohort (4 patients, 33%) showed a mean ΔAgeBone of 18.33 ± 6.47 years and mean ΔAgeBlood of 16.93 ± 4.02 years. In comparison, the survival cohort showed a significantly lower mean ΔAgeBone and ΔAgeBlood (7.86 ± 6.7 and 7.31 ± 7.71 years; p = 0.026 and 0.039, respectively). Bone-derived methylation age was strongly correlated with blood-derived methylation age (R = 0.81; p = 0.0016). Bone-derived DNA methylation clocks were found to be both feasible and strongly correlated with those derived from whole blood within a geriatric hip fracture population. Mortality was independently associated with the DNA methylation age, and that age was approximately 17 years greater than chronological age in the mortality cohort. The results of the present study suggest that prevention of advanced DNA methylation may play a key role in decreasing mortality following hip fracture. Prognostic Level I. See Instructions for Authors for a complete description of levels of evidence.

The genomic landscape of papillary thyroid carcinoma on next-generation sequencing in patients undergoing total thyroidectomy.

Thyroidectomy is increasingly performed for suspected malignancy. This cohort study aimed to identify genetic markers associated with malignancy and determine the molecular landscape of papillary thyroid carcinoma (PTC) through next-generation sequencing (NGS) in patients undergoing total thyroidectomy. Among 116 surgical candidates, 103 patients (age=42.9±13.7years; Male: Female=14:89) with benign or malignant thyroid nodules were eligible. Live thyroid tissue samples harvested intraoperatively with adequate DNA and RNA yield were subjected to NGS on the Illumina NovaSeq 6000 platform for genomic and transcriptomic analysis, respectively. Histopathology comprised 20 malignant (19.4%) and 83 benign (80.6%) cases, including 16 PTC (15.5%) cases. On NGS, single nucleotidepolymorphisms (SNPs) in NTRK1 at NC_000001.11:156879016 on chromosome 1 and ALK at NC_000002.12:29717663 on chromosome 2 were frequent in malignant lesions (p<0.05). A SNP in ALK at NC_000002.12:29193706 was consistently a homozygous alternate alleleacross the cohort. DNA-sequencing of PTC lesions identified recurrentsomatic mutations in BRAF (100%), ALK (56.3%), RET (18.8%), PIK3CA (12.5%), NTRK1 (12.5%), NTRK2 (87.5%), NTRK3(12.5%), NRAS(6.3%), and PTCH1 (31.3%) genes. RNA sequencing revealednovelfusiongenes, including MKRN1-BRAF, RN7SL1-CDH1, IRF2BPL-MED12, MED12-IRF2BPL, CPM-MDM2, and AC005895.3-PDGFRB. Inreceiveroperative characteristics analysis, the AUCs ofALKmutationpredictingrecurrence and metastases were 0.818 and 0.783. This Indian study identified novel somatic mutations and fusion genes in PTC, revealing a distinct genomic landscape with implications in precision diagnostics and personalized therapies. NGS with intraoperative live sampling shows promise in prognostication and therapeutic optimization of advanced/metastatic PTC cases. CTRI/2020/09/027607dt 04/09/2020; REF/2020/08/036119.

ВЛИЯНИЕ ЭКСТРАКОРПОРАЛЬНОЙ АУТОГЕМОМАГНИТОТЕРАПИИ В ИНТРАОПЕРАЦИОННОМ ПЕРИОДЕ ПРИ ПРОВЕДЕНИИ РЕВАСКУЛЯРИЗАЦИИ МИОКАРДА В УСЛОВИЯХ ИСКУССТВЕННОГО КРОВООБРАЩЕНИЯ НА КИСЛОТНО-ЩЕЛОЧНОЕ СОСТОЯНИЕ АРТЕРИАЛЬНОЙ КРОВИ

Background. To evaluate changes in acid-base balance in patients with coronary heart disease in the intraoperative period during coronary artery bypass grafting under artificial circulation using extracorporeal autohemomagnetotherapy (EAHMT). To consider the presence of a negative effect of this technique on acid-base balance. To study the possible relationship between the polymorphism of the angiotensin-1 receptor gene (AGTR1 A1166C), endothelin-1 (EDN1 Lys 198 Asn), endothelial nitric oxide synthase (NOS3 C786T) and changes in the studied parameters of acid-base balance. Material and methods. Group 1 included standard anesthesia for coronary artery bypass grafting under cardiopulmonary bypass without the use of EAHMT (60 patients). Group 2 included standard anesthesia for coronary artery bypass grafting under cardiopulmonary bypass with the use of EAHMT (63 patients). The following parameters of the acid-base balance of arterial blood were assessed: hydrogen index (pH), lactate (Lac), base deficit (SBE), potassium (K), sodium (Na), hemoglobin (Hb), hematocrit (Hct). All patients of both groups underwent intraoperative venous blood sampling from the central venous catheter. Then, the polymerase chain reaction method was used to study the genotypes of the angiotensin-1 receptor gene polymorphism (AGTR1 A1166C), endothelin-1 (EDN1 Lys 198 Asn), endothelial nitric oxide synthase (NOS3 C786T). Results. At the second stage of the study, a decrease in the hydrogen index of arterial blood, hemoglobin, hematocrit, and base deficit was revealed in both groups. A statistically significant increase in lactate and potassium was obtained in both study groups. No associations were found between the polymorphism of the angiotensin-1 receptor gene (AGTR1 A1166C), endothelin-1 (EDN1 Lys 198 Asn), endothelial nitric oxide synthase (NOS3 C786T) and the arterial blood acid-base balance. Conclusion. The use of EAHMT does not have negative impact on the electrolyte balance and acid-base composition of the blood. The presence of polymorphism of the AGTR1 gene A1166C (rs 5186), EDN1 gene Lys 198 Asn (rs5370), NOS3 gene C786T (rs 2070744) does not affect the acid-base balance of arterial blood.

P32 A case of disseminated pneumococcal infection with musculoskeletal manifestations

Abstract Introduction Septic arthritis should be the first consideration in any patient presenting with a hot, swollen joint. Infection may affect one or more joints, and bacteria typically enter the joint through direct inoculation, haematogenous seeding, or spread from adjacent soft tissue or bone infection. Staphylococcus aureus is the most common causative organism. Streptococcus pneumoniae is an uncommon cause of septic arthritis, accounting for approximately 5% of cases. We present the case of a 78-year-old male with no significant medical history who presented with a polyarticular pattern of joint inflammation related to disseminated pneumococcal infection. Case description The patient presented with a one week history of gradual onset pain and swelling in the right knee and right wrist. He was previously well and remained physically active. He was a non-smoker, drank moderate alcohol and had no history of intravenous drug use. He had no current or preceding infective symptoms, including respiratory tract symptoms, nor history of trauma or recent foreign travel. Examination revealed a warm right knee effusion with restricted range of movement. There was swelling of both wrists (right more than left), both second metacarpophalangeal joints and the left ankle. There were no heart murmurs or peripheral stigmata of endocarditis. He was afebrile and haemodynamically stable. Admission blood tests showed WBC 21 x109/L, neutrophils 18 x109/L, CRP 369 mg/L, urate 452 µmol/L and procalcitonin 3.84 µg/L. Rheumatoid factor was 25.3 IU/mL with negative anti-CCP. Knee X-ray showed significant medial compartment osteoarthritis. Hand and wrist X-rays were unremarkable. Synovial fluid aspirate from the right knee grew Streptococcus pneumoniae and calcium pyrophosphate crystals were also seen on polarised light microscopy. Blood cultures were positive for the same organism. The patient underwent arthroscopic washout of the knee and was treated with colchicine and intravenous amoxicillin. He was taken to theatre for a right wrist washout, however the wrist was found to be clean and dry intraoperatively. He had two further washouts of the right knee and repeat intraoperative samples and blood cultures were negative. Additional screening for HIV, syphilis and myeloma was negative. Transthoracic echocardiogram showed no vegetations. CT chest showed basal atelectasis but no focal consolidation. Left hand and wrist MRI showed extensor compartment tenosynovitis and second metacarpophalangeal joint synovitis. His antibiotics were switched to intravenous ceftriaxone and oral doxycycline. He clinically improved and was discharged with a plan to complete a 6-week course with outpatient review. Discussion Streptococcus pneumoniae is an uncommon cause of septic arthritis, responsible for approximately 5% of all cases, but more often causes polyarticular infection than other organisms. This may be related to higher rates of bacteraemia in patients with pneumococcal septic arthritis. In one review of 190 cases of pneumococcal septic arthritis, polyarticular infection was present in 36% of patients and 72% had concomitant bacteraemia (compared with rates of approximately 20% polyarticular infection and 30-50% bacteraemia for septic arthritis overall). The joints most commonly affected are the knee, followed by the hip, shoulder, ankle and elbow. The original focus of infection is most commonly pneumonia or meningitis, but up to 50% of patients have no identifiable extra-articular source of infection. Pneumococcal septic arthritis more commonly affects patients with predisposing risk factors, such as rheumatoid arthritis, osteoarthritis, joint prosthesis, alcoholism, myeloma and other malignancies, diabetes and immunosuppression. Our patient had no specific predisposing medical conditions other than knee osteoarthritis, and his age was likely to be his main risk factor. It is also important to note that septic arthritis in the elderly can present atypically, with insidious onset and absence of fever or other signs of systemic infection. This was the case in our patient, who despite bacteraemia and markedly elevated inflammatory markers, did not otherwise appear floridly septic or unwell. Our patient presented with a polyarticular pattern of joint inflammation, although joint infection was only ultimately confirmed in the right knee. Also notable was the presence of calcium pyrophosphate crystals in the aspirate. One might theorise whether the infection might have triggered a reactive polyarthropathy or concurrent crystal arthritis. It is well recognised that septic arthritis and crystal arthritis can coexist in the same patient. The case also highlights the value in sampling multiple joints and taking blood cultures in such patients. Key learning points • Polyarthritis does not exclude the possibility of septic arthritis • Joint aspiration should be performed in all patients presenting with a hot, swollen joint • In cases of polyarthritis, consideration should be given to aspiration of all affected joints and taking blood cultures, particularly in the elderly and patients with predisposing risk factors for septic arthritis • Septic arthritis can present atypically in the elderly, with the absence of fever and other typical signs of systemic infection

Improving the microbiological diagnosis of fracture-related infection and prosthetic joint infection through culturing sonication fluid in Bactec blood culture bottles.

Sonication of surgically removed implants appears to optimize the microbiological diagnosis in orthopedic implant-associated infections (OIAI). However, reports of infection with negative cultures can still reach high rates. A study evaluating the inoculation of sonication fluid into blood culture bottles (SFBCB) in patients with fracture-related infection (FRI) and prosthetic joint infection (PJI) is necessary. This study compared the accuracy SFBCB over the conventional sonication fluid cultures (CSFC) and tissue culture (TC). Consecutive patients who underwent implant removal surgeries due to any reason had their implants sonicated according to standardized method. Definitions of PJI and FRI were based upon criteria by European Bone and Joint Infection Society (EBJIS) and Metsemakers, respectively. Between three to five intraoperative tissue samples were processed. The implant`s sonication fluid was seeded onto sheep blood agar, chocolate agar, thioglycolate broth and on tryptic soy broth for CSFC, while was also inoculated into blood culture bottles and incubated in the automated system during 5 days for SFBCB. Overall, 74 patients were analyzed, of which 57 with OIAI (48 FRI and 09 PJI) and 17 aseptic failures (03 arthroplasties and 14 osteosynthesis). Interestingly, SFBCB demonstrated significantly higher sensitivity compared to CSFC (96.5% [95% CI, 88-100] vs. 78.9% [95% CI, 66-89], p = 0.004), and to TC (96.5% [95% CI, 88-100], vs. 57.9% [95% CI, 44-71], p < 0.001), whereas there were no significant differences in specificity between the three methods. In comparison to CSFC and TC, SFBCB improved sensitivity for diagnosing OIAI without compromising specificity.

Utility of intraoperative Delphian lymph node sampling in pediatric thyroid surgery

ObjectivesThe Delphian lymph node (DLN) is the first lymph node receiving drainage from the thyroid. We aim to determine whether routine DLN sampling with frozen section analysis during pediatric thyroidectomy can alter intraoperative surgical decision making. Additionally, we aim to measure whether DLNs can predict a requirement for central neck dissection (CND) in the clinically node negative (CNN) pediatric population. MethodsRetrospective chart review for pediatric patients who underwent thyroidectomy between 2014 and 2022. Patients were included if they had prior FNA with a result of: benign nodule, atypia or follicular neoplasm of undetermined significance (AUS/FNUS), follicular neoplasm (FN), or papillary thyroid carcinoma (PTC). All patients had intraoperative DLN analysis via frozen section histopathology. Results27 patients were included, 9 males (33 %) and 18 females (67 %). On final pathology 19 patients (70.4 %) had PTC. The DLN was negative for carcinoma in all (n = 8, 100 %) patients with benign pathology. In 10 patients (100 %) with positive DLN on frozen section, postoperative pathology demonstrated central neck metastasis. Nine (90 %) of these patients were CNN and had alterations in the surgical plan based on the DLN. The tenth patient's surgical plan did not change given preoperative clinical disease. Three patients with negative DLNs had central neck metastasis. ConclusionThe DLN serves a role in guiding treatment for the pediatric population. Positive DLN altered surgical plans in 60 % of CNN PTC patients, allowing for CND to be performed and reducing need for additional surgical resection. The positive predictive value for DLN status was 100 % in this study, and the negative predictive value was 62.5 %. However, negative DLNs do not rule out central neck disease.

CELL-INTRINSIC METABOLIC PHENOTYPES IDENTIfiED IN GLIOBLASTOMA PATIENTS USING MASS SPECTROMETRY IMAGING OF 13C-LABELED GLUCOSE METABOLISM

Abstract AIMS Glioblastoma (GB) is an inherently heterogenous and invasive primary brain tumour. Genetic and transcriptomic studies have attempted to classify GB into subtypes that can identify therapeutic vulnerabilities and predict survival. An outstanding question and technical challenge is to visualise the metabolism of a tumour within its native microenvironment and understand to what extent its metabolism is driven by the microenvironment. METHOD Patients with GB tumours were infused with [U-13C]glucose and intra-operative multi-regional tumour samples were rapidly snap frozen for metabolic tracing analysis using mass spectrometry imaging (MSI). Tissue microenvironment was assessed using multiplexing of antibodies on immunocytochemistry (IMC) of parallel sections. Isotope tracing in human derived neurospheres and patient derived xenografts were used to confirm the presence of metabolic phenotypes detected in the human samples and to test susceptibility of each phenotype to a panel of drugs targeting cellular metabolism. RESULTS Three metabolic signatures were identified in patient GB tumours: glycolytic, oxidative and a mixed glycolytic/oxidative phenotype. The phenotypes did not correlate with microenvironmental features, including proliferation rate, immune cell infiltration, and vascularisation. The phenotypes were retained when patient derived cells were grown in vitro, or as orthotopically implanted xenografts, and were robust to changes in oxygen concentration, demonstrating their cell intrinsic nature. The spatial extent of the regions occupied by cells displaying these distinct metabolic phenotypes are large enough to be detected using clinically applicable metabolic imaging techniques. The phenotypes also demonstrate differential drug sensitivities. CONCLUSION This is the first report to demonstrate high resolution imaging of metabolic fluxes in a human tumour in vivo. In conjunction with studies on patient-derived neurospheres and orthotopically implanted xenografts we have demonstrated the presence of different metabolic phenotypes within GB that are tumour cell intrinsic and largely independent of the tumour microenvironment. These can be imaged clinically and used to stratify patients for personalised therapy.

Pediatric macular hole associated with vitreoretinal traction on epiretinal lesions – a case report and literature review

Purpose: We describe a case of non-traumatic macular hole in a pediatric patient associated with numerous epiretinal lesions throughout the macula. Methods: A healthy 9-year-old girl presented to retina clinic with several months of blurry vision in the right eye. Clinically, there was a full-thickness macular hole with serous detachment and white epiretinal tufts. Spectral-domain optical coherence tomography confirmed the presence of the full-thickness macular hole with hyperreflective epiretinal proliferations in the right eye and an unremarkable left eye. Systemic work-up was negative. After a short period of observation, the patient underwent vitrectomy with internal limiting membrane peel and 14% C3F8 gas tamponade in the right eye. Multiple intraoperative samples were sent for further testing, which were also negative. Results: At one and six-month postoperative visits, examination showed successful closure of the full-thickness macular hole with resolution of the subretinal fluid and improved visual acuity. Conclusion: Non-traumatic macular holes in pediatric patients warrant systemic and ocular work-up, including fluorescein angiography and lab testing. Good anatomic and visual outcomes are generally seen with spontaneous and surgical closures of macular holes in this age group. Early vitrectomy with histological analysis of ocular samples should be considered in pediatric macular hole cases associated with vitreoretinal traction, especially those with epiretinal abnormalities.

A-048 Reference Interval and Clinical Performance Studies for Vitros® Immunodiagnostic Products Intact PTH II Assay to Aid in Diagnosis of Calcium and Parathyroid Disorders and Intraoperative Testing

Abstract Background Intact parathyroid hormone (iPTH) measurements aid in the differential diagnosis of hypercalcemia, hypocalcemia, and parathyroid disorders. The National Academy of Clinical Biochemistry has established guidelines for intraoperative PTH testing to monitor surgical success during parathyroidectomies. Studies were conducted to define the reference interval and clinical performance of the Vitros Immunodiagnostic Products Intact PTH II (Vitros iPTH II) assay, using samples from healthy individuals and patients with conditions commonly requiring iPTH testing, including intraoperative cases. Methods The reference interval study was conducted in accordance with Clinical and Laboratory Standards Institute (CLSI) guideline EP28-A3c in serum samples from 134 healthy individuals. For the clinical performance study, serum samples from individuals with hypoparathyroidism, primary hyperparathyroidism, chronic renal failure (secondary or tertiary hyperparathyroidism), hypercalcemia, hypercalcemia of malignancies, and hypocalcemia were tested. Intraoperative samples used were collected from parathyroidectomy patients in series at each surgical timepoint along with the standard plasma samples used to determine surgical success. Results The reference samples were composed of 134 serum donors that met all inclusion/exclusion criteria for healthy donors and had a normal test result on calcium, TSH, alkaline phosphatase, creatinine, and phosphate assays. The reference interval for iPTH was determined to be 14.2-75.2 pg/mL. The results in various disease states demonstrated the clinical performance of the Vitros iPTH II assay. Of 32 intraoperative sample series included in the study, three samples demonstrated no intraoperative decrease in iPTH due to surgical failures. Consistent with the goal of the parathyroidectomy procedure, at least a 50% decrease in iPTH was observed between the presurgical and post-excision samples in all other sample series. The clinical concordance with the Roche PTH assay used intraoperatively in these procedures was 100%. Conclusions Defining the reference interval for a normal healthy population and results from the intended use population demonstrated that the Vitros iPTH II assay can be used as an aid in the diagnosis of calcium and parathyroid disorders and intraoperative testing.

Do Intra-articular Metal Ion Levels Predict Adverse Local Tissue Reaction in Revision Total Hip Arthroplasty for Mechanically Assisted Crevice Corrosion?

BackgroundMechanically assisted crevice corrosion is a complication that may occur in vivo at modular metal interfaces following metal-on-polyethylene total hip arthroplasty (THA). Metal ions released in vivo may be associated with adverse local tissue reactions (ALTRs). While there is no definitive value, high serum ion levels are implicated as contributors to ALTR, and various screening levels have been recommended. The purpose of this investigation was to evaluate the relationship between synovial fluid (SF) cobalt and chromium ion levels and the risk of developing ALTR. MethodsThis was a retrospective cohort study of 552 patients who underwent 621 metal-on-polyethylene primary THAs. A total of 69 patients underwent revision THA due to symptomatic primary failure with elevated serum metal ions levels. There were 28 who had preoperative serum and intraoperative SF chromium and cobalt samples. Patient demographics, surgical, and laboratory data were collected. Descriptive statistics, Mann-Whitney U, analysis of variance tests, and linear regression analyses were performed. ResultsThere were 40.6% of revisions that had preoperative serum and intraoperative SF samples. The mean time to revision was 5.7 (range, 3.8 to 7.6) years. Mean SF cobalt and chromium levels were 870.9mcg/L (range, 1.1 to 8,300.0) and 573.5mcg/L (range, 1.3 to 10,000.0). Mean serum and SF cobalt-chromium ratios were 4.0 (range, 0.9 to 7.1) and 6.4 (range, 0 to 15.1), respectively. Elevated serum cobalt levels were predictive of ALTR (P = 0.002), SF levels were not. Analysis of preoperative serum to SF cobalt-chromium ratios showed poor correlation (R2 = 0.05). ConclusionsThere was no correlation between SF ion levels and ALTR. Also, serum and intra-articular ion levels did not correlate. The SF levels did not provide additional value over serum levels for diagnosis or prognosis of mechanically assisted crevice corrosion. Further studies are needed to better understand the relationship between serum and SF ion levels and its relationship to ALTR.

Performance of the GeneXpert® MRSA/SA SSTI Test in Periprosthetic Joint Infections: Rate of failure, Outcomes and Risk Factors

BackgroundThe GeneXpert® MRSA/SA SSTI test allows early detection of methicillin-resistant staphylococci in intraoperative samples of prosthetic joint infections (PJI) in order to stop early broad-spectrum antibiotics. Questions/Purpose(1) What is the rate of false-negative GeneXpert® MRSA/SA SSTI test results? (2) Does a false-negative GeneXpert® MRSA/SA SSTI test result increase the risk of treatment failure for the patient with a PJI? (3) What are the risk factors of a false-negative result? MethodA retrospective study was carried out to compare all GeneXpert® assays to conventional cultures in prosthetic joint infections from April 1st, 2012 to October 1st, 2016. False-negative (FN) results (absence of methicillin-resistant staphylococci (MRS) with GeneXpert® test, but presence in the culture) were identified. We compared the rate of treatment failure between FN results and other test results and we established the risk factors of having a FN result. ResultsAmong the 612 GeneXpert® results, the rate of FN results was 3.6 % (22/612). We found a significant increase in treatment failures for prosthetic joint infection with a FN result with 14 treatment failures (14/22) compared to 198 treatment failures (198/590) in the other test results (OR, 2.1; 95 % CI, 1.3-3.4, p = 0.0019). Not considering suppressive antibiotics as a treatment failure, we found no significant difference in the rate of treatment failures between the false-negative tests and the other tests (OR, 1.36; 95 % CI, 0.66-2.81, p = 0.41). Tobacco use (OR, 3.8; 95 % CI, 1.4-10.3, p = 0.004), ASA classification (OR, 2,4; 95 % CI, 0.9-6.9, p = 0.064), history of infection in the joint (OR, 3.2; 95 % CI, 1.2-9.6, p = 0.007), chronic infections (OR, 3.2; 95 % CI, 0.8-17.5, p = 0.01) and polymicrobial infections (OR, 3.2; 95 % CI, 1.1-9.2, p < 0.0001) were risk factors for a FN result. ConclusionGeneXpert® tests in prosthetic joint infections showed a low rate of FN results. An increased risk of treatment failures was observed in FN results only when long-term use of suppressive antibiotics was considered as treatment failure. Level of evidenceIII; Diagnostic retrospective case control study.

Nd-YAG laser-assisted pulmonary metastasectomy: initial experience from a tertiary care cancer center in India.

Pulmonary metastasectomy is recommended for metastatic lung lesions when R0 resection is possible, the primary site is in controlled status, surgery is of low risk, and extrathoracic metastases are absent. We present the initial experiences of laser-assisted surgery (LAS) for pulmonary metastatic lesions from a tertiary care cancer center in India. All patients undergoing non-anatomical pulmonary metastasectomy between September 2022 and January 2023 for synchronous and metachronous lesions, operated on by a single consultant thoracic oncosurgeon in a tertiary care center of India, were identified from a prospective database. Ten patients with 124 metastatic lesions were included in the study. A hybrid approach (video-assisted thoracoscopic surgery (VATS) with mini-thoracotomy) was performed. Measurements of total lesion volume and lung parenchyma resected were taken from the final histopathological analysis of the intraoperative sample. LAS was performed for 102 lesions and stapled wedge resection for 22 lesions. Evidence of malignancy was noted in 88/102 (86.3%) of the lesions excised. Patients with LAS had advantages of parenchyma preservation, less postoperative morbidities, and shorter hospital stays. LAS of pulmonary metastatic lesions addresses more lesions in a single sitting; the bilateral lung lesions can be operated and has parenchyma preserving and good sealant properties. The online version contains supplementary material available at 10.1007/s12055-024-01723-8.

Potential of Current Direct Mechanical Testing Methods in Assessing Intraoperative Samples of Aortic Aneurysm Caused by Uncontrolled Arterial Hypertension

Potential of Current Direct Mechanical Testing Methods in Assessing Intraoperative Samples of Aortic Aneurysm Caused by Uncontrolled Arterial Hypertension

The maternal microbiome in normal pregnancy and at delivery by cesarean section and the early developmental phase of the neonatal microbiome—presentation of a longitudinal pilot study

Abstract Aim In this study by Foessleitner et al., both the maternal microbiome in the third trimester of pregnancy and the factors that influence the development of the child’s microbiome after cesarean delivery were investigated. Methods Maternal vaginal and rectal swabs were collected at inclusion in the last trimester of pregnancy and on the day of the cesarean section. In addition, placental and intrauterine swabs as well as infant dermal, buccal, and meconium swabs were taken during the cesarean section immediately after birth and subsequently on the second/third day of life. All samples were analyzed for microbial composition using 16s rRNA amplicon sequencing. Results A total of 30 mothers and their newborns were included in the study, with microbiome samples available for all maternal, intrauterine cavity, and placenta samples, as well as for 18 out of the 30 newborns. The vaginal and rectal microbiome was stable over the course of the third trimester and showed no significant changes (permutational multivariate analysis of variance [PERMANOVA]; p &gt; 0.05). Both the intraoperative samples (placental, intrauterine) and the neonatal swabs at the time of birth were consistently sterile. However, rapid infant microbial colonization subsequently occurred, with neonatal buccal mucosa and stool samples showing significantly different microbial colonization from their mothers as early as the second/third day of life (PERMANOVA; p &lt; 0.01). Conclusion The conclusion of the presented study was therefore that the vaginal and rectal microbiome of healthy pregnant women does not change in the last trimester, the infant and the placenta are not microbially colonized at the time of birth, and the development of the newborn’s microbiome after birth appears to be influenced mainly by environmental exposure.

Documentation of critical intraoperative oncologic findings: Synoptic versus narrative operative reports for childhood cancer surgery.

Documentation of intraoperative oncologic findings varies greatly across narrative operative reports (NRs). An international panel of childhood cancer experts recently developed a synoptic operative report (SR) for childhood cancer surgeries. The aim of this study was to compare the documentation of critical intraoperative findings in NRs versus SRs. A single-center retrospective review of all surgical resections of primary solid tumors at our pediatric oncology center was conducted from June 2023 to March 2024, after an institutional SR was piloted from October 2023 onwards. Data collected included the presence or absence of six components included in standard pediatric oncology NRs. Inclusion rates were calculated as percentages for each component. Due to the small sample, the Fisher's exact test was used for all hypothesis testing. Seventy primary tumor resections were performed during the study period, as documented by 38 NRs and 32 SRs. All operative reports after October 2023 were SRs. Completeness of tumor resection and specimen naming were consistently documented in NRs (86% and 100%, respectively) and SRs (100% and 100%, respectively). The presence/absence of three components-intraoperative tumor spillage (31%), vascular involvement (31%), and lymph node sampling (26%)-were documented in fewer than a third of the NRs. Documentation of the presence/absence of locoregional spread, intraoperative tumor spillage, vascular involvement, and lymph node sampling was significantly better in SRs than in NRs. Adoption of SRs significantly improved the documentation of critical intraoperative findings. Thus, we recommend using SRs in pediatric solid tumor surgery.