Intraoperative variability of corneal epithelium thickness in photorefractive keratectomy.

PURPOSE: To evaluate the intraoperative central corneal epithelial thickness (ET) as measured by optical coherence pachymetry (OCP) in myopic eyes undergoing alcohol-assisted photorefractive keratectomy (PRK). METHODS: A retrospective review of patients who underwent alcohol-assisted PRK was performed. Data were abstracted on age, gender, contact lens (CL) wear, preoperative refractive errors, keratometry, topographic and ultrasonic pachymetry, and intraoperative OCP measurements before and after epithelium removal. The central ET was calculated by subtracting OCP measurement after epithelium removal from the OCP measurement prior to epithelium removal. RESULTS: The study comprised of 162 consecutive eyes from 81 patients. Mean age was 26.73 ± 6.47 years, 50.6% were males. CL was used in 92 eyes (56.8%). The mean sphere and spherical equivalent were -3.60 ± 1.84 D and -3.26 ± 1.85D, respectively. The mean intraoperative ET was 58.22 ± 17.53 µm (range, 15-121µm). Fifty-five percent of the eyes had an ET measurement above or below the range of 40-60µm. ET was significantly higher in the second operated eye compared to the first operated eye (p = 0.006), and an association was found to CL-wear (p = 0.03). There was no significant difference in thickness between genders (p = 0.62), and no correlation to patient age (p = 0.45, rp = 0.06), refractive errors (p > 0.30,rp=-0.07-0.08), nor keratometry(p > 0.80, rp=-0.01- (-0.02)). CONCLUSION: The intraoperative assessment of ET in alcohol-assisted PRK showed a high variability of the central corneal epithelium, with a significant difference between the first and second operated eyes. This difference may have implications when the epithelium is not included in the surgical planning in surface ablation.

A multicenter proof-of-concept study on deep learning-based intraoperative discrimination of primary central nervous system lymphoma.

Accurate intraoperative differentiation of primary central nervous system lymphoma (PCNSL) remains pivotal in guiding neurosurgical decisions. However, distinguishing PCNSL from other lesions, notably glioma, through frozen sections challenges pathologists. Here we sought to develop and validate a deep learning model capable of precisely distinguishing PCNSL from non-PCNSL lesions, especially glioma, using hematoxylin and eosin (H&E)-stained frozen whole-slide images. Also, we compared its performance against pathologists of varying expertise. Additionally, a human-machine fusion approach integrated both model and pathologic diagnostics. In external cohorts, LGNet achieved AUROCs of 0.965 and 0.972 in distinguishing PCNSL from glioma and AUROCs of 0.981 and 0.993 in differentiating PCNSL from non-PCNSL lesions. Outperforming several pathologists, LGNet significantly improved diagnostic performance, further augmented to some extent by fusion approach. LGNet's proficiency in frozen section analysis and its synergy with pathologists indicate its valuable role in intraoperative diagnosis, particularly in discriminating PCNSL from glioma, alongside other lesions.

Intraoperative Performance and Early Postoperative Outcomes Following Phacoemulsification With Three Fluidic Systems: A Randomized Trial.

PURPOSE: To compare intraoperative performance and early postoperative outcomes following phacoemulsification with two systems using active fluidics and one using gravity-based fluidics. METHODS: In this prospective randomized trial, 200 eyes were randomized to the traditional and Active Sentry groups (n = 80 eyes each) where the Centurion Vision System was used with traditional or Active Sentry (Alcon Laboratories, Inc) hand-pieces, respectively, or the Infinit group (n = 40 eyes) where the Infiniti Vision System (Alcon Laboratories, Inc) was used. Within the traditional and Active Sentry groups, there were two subgroups with low (30 mm Hg) or high (55 mm Hg) intraocular pressure (IOP) used. Outcome measures compared were: cumulative dissipated energy (CDE), percentage change in central corneal thickness (CCT) at 1 day, 1 week, and 1 month, anterior chamber cells at 1 day and 1 week, rate of rise and fall of IOP following occlusion break, corneal endothelial cell density (ECD), and macular thickness 6 months postoperatively. RESULTS: CDE was significantly lower in group II compared to the traditional group (2.96 ± 1.4 vs 4.14 ± 2.2, P = .001). With 30 mm Hg IOP, the Active Sentry group had significantly less percentage change in CCT at 1 week postoperatively compared to the traditional handpiece group (0.01% vs 0.02%, P = .008). Incidence of anterior chamber cells less than grade 2 on day 1 was significantly higher in the Active Sentry group (82.9% vs 52%, P = .03). Percentage change in ECD was significantly lower in the Active Sentry group (-0.957 vs -0.98%, P = .005). Significantly faster rise of IOP to baseline following occlusion break was seen in the Active Sentry group. CONCLUSIONS: The use of Active Sentry handpiece was associated with lower CDE, less postoperative increase in CCT, fewer anterior chamber cells, and faster rise of IOP following occlusion break. [J Refract Surg. 2024;40(5):e304-e312.].

Potential rapid intraoperative cancer diagnosis using dynamic full-field optical coherence tomography and deep learning: A prospective cohort study in breast cancer patients.

An intraoperative diagnosis is critical for precise cancer surgery. However, traditional intraoperative assessments based on hematoxylin and eosin (H&E) histology, such as frozen section, are time-, resource-, and labor-intensive, and involve specimen-consuming concerns. Here, we report a near-real-time automated cancer diagnosis workflow for breast cancer that combines dynamic full-field optical coherence tomography (D-FFOCT), a label-free optical imaging method, and deep learning for bedside tumor diagnosis during surgery. To classify the benign and malignant breast tissues, we conducted a prospective cohort trial. In the modeling group (n = 182), D-FFOCT images were captured from April 26 to June 20, 2018, encompassing 48 benign lesions, 114 invasive ductal carcinoma (IDC), 10 invasive lobular carcinoma, 4 ductal carcinoma in situ (DCIS), and 6 rare tumors. Deep learning model was built up and fine-tuned in 10,357 D-FFOCT patches. Subsequently, from June 22 to August 17, 2018, independent tests (n = 42) were conducted on 10 benign lesions, 29 IDC, 1 DCIS, and 2 rare tumors. The model yielded excellent performance, with an accuracy of 97.62%, sensitivity of 96.88% and specificity of 100%; only one IDC was misclassified. Meanwhile, the acquisition of the D-FFOCT images was non-destructive and did not require any tissue preparation or staining procedures. In the simulated intraoperative margin evaluation procedure, the time required for our novel workflow (approximately 3 min) was significantly shorter than that required for traditional procedures (approximately 30 min). These findings indicate that the combination of D-FFOCT and deep learning algorithms can streamline intraoperative cancer diagnosis independently of traditional pathology laboratory procedures.

Differences in Intraoperative Fluoroscopic Radiation Exposure During Ankle Fracture Open Reduction and Internal Fixation Between Orthopaedic Surgery and Podiatry.

Surgical ankle fractures pose a unique situation because both podiatrists and orthopaedic surgeons manage these injuries. Intraoperative fluoroscopy is routinely used; however, excessive radiation can be harmful to both the patient and the surgical team. The primary goal of this study was to determine whether there is a difference in the amount of intraoperative radiation exposure during ankle fracture open reduction and internal fixation (ORIF) when performed by orthopaedic surgeons versus podiatrists. This is a retrospective review of patients who underwent ankle fracture ORIF at an urban level I trauma center between January 1st, 2018, and April 1st, 2023. The electronic health record was queried using International Classification of Diseases nine and 10 codes associated with ankle fractures. Patients aged older than 18 years with an ankle fracture managed surgically were included. Subjects were then stratified by procedure. The mean total radiation dose (mRad) and mean total fluoroscopic time (seconds) were then compared between those performed by orthopaedic surgeons and podiatrists. Of the 333 included procedures, 186 were done by orthopaedic surgeons and 147 were done by podiatrists. Using multiple linear regression analysis to control for age, sex, race, ethnicity, and body mass index, patients undergoing isolated malleolus ORIF with syndesmosis repair performed by orthopaedic surgery were found to have a significantly lower mean fluoroscopic time compared with those performed by podiatry (68.4 s versus 104.8 s; P = 0.028). In addition, trimalleolar ORIF with syndesmotic repair performed by orthopaedic surgery had a significantly lower mean total radiation dose compared with those performed by podiatry (244.6 mRad v 565.6 mRad; P = 0.009). Patients and surgical teams are exposed to markedly less radiation in isolated malleolar and trimalleolar fracture ORIF with syndesmosis repair when performed by an orthopaedic surgeon as compared with those performed by a podiatrist.

111 In-Pentetreotide-Guided Radiosurgery for Intraoperative Localization of Retroperitoneal Nodal Metastasis in a Patient With Ileal Neuroendocrine Tumor.

ABSTRACT: 64 Cu-DOTATATE PET/CT of a 44-year-old man with an ileal neuroendocrine tumor demonstrated the primary tumor, local nodal metastases, and a pericaval nodal metastasis. Localization of the pericaval node during surgery may be difficult, thus 4.4 mCi of 111 In-pentetreotide was administered before surgery to assist with localization and resection. At surgery, the pericaval nodal metastasis was readily detected by gamma probe, which could then be resected and pathologically proven to be a metastasis. This demonstrates the use of somatostatin receptor-targeted imaging for intraoperative localization of an otherwise difficult to surgically localize metastasis. Without intraoperative somatostatin receptor-targeted radiosurgery, disease may have been incompletely resected.

Comparison of Intraoperative Imprint Cytology versus Frozen Section for Sentinel Lymph Node Evaluation in Breast Cancer. A study along with Systematic Review and Meta-analysis of literature.

BACKGROUND: Sentinel lymph node (SLN) is the first lymph node to drain the lymph from a particular region involved by cancer. The commonly performed intraoperative methods for SLN evaluation are touch imprint cytology (TIC) and frozen section (FS). The present study aimed to determine the sensitivity, specificity and accuracy of TIC and FS with histopathological diagnosis as gold standard. MATERIALS AND METHODS: The nodes were bissected along their long axis and wet surface was imprinted on to clean glass slides followed by toluidine blue and rapid Papanicolaou staining. Subsequently the lymph node slices were cut at three levels using the cryostat machine and stained with Hematoxylin and eosin stain. The cytological and FS findings were compared and the specificity, sensitivity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) of TIC and FS was evaluated taking histopathological diagnosis as gold standard. In addition, pooled sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for touch imprint cytology and frozen section were assessed for the studies included in the meta-analysis. RESULTS: The specificity, sensitivity, diagnostic accuracy, positive predictive value and negative predictive value of touch imprint cytology were 100%, 88.2%, 90%, 100% and 60% respectively. The specificity, sensitivity, diagnostic accuracy, PPV and NPV of frozen section were 100%, 94.1%, 95%, 100% and 75% respectively. The sensitivity of TIC and FS for detection of micrometastasis was 60% and 80% respectively. The pooled sensitivity and specificity for touch imprint cytology were 85.24% (95% CI, 83.46%-86.90%), and 98.99% (95% CI, 98.69%-99.23%) respectively. The pooled sensitivity and specificity for frozen section examination were 90.45% (95% CI, 85.15%-94.34%), and 100% (95% CI, 99.24%-100%) respectively. CONCLUSION: Even though the sensitivity of FS was better than imprint cytology in detection of micrometastasis, TIC is a rapid inexpensive technique which can be utilized in remote areas in absence of cryostat machine. The sensitivity of the two techniques with respect to detection of macrometastasis was comparable. This meta-analysis highlights the accuracy of the touch imprint cytology and frozen section examination in the intra-operative detection of malignancy in breast cancer.

Evaluation of different body temperature measurement methods for patients in the intraoperative period.

OBJECTIVES: this study aimed at estimating and comparing the reliability of temperature measurements obtained using a peripheral infrared temporal thermometer, a central cutaneous thermometer ("Zero-Heat-Flux Cutaneous thermometer") and an esophageal or nasopharyngeal thermometer among elective surgical patients in the intraoperative period. METHOD: a longitudinal study with repeated measures carried out by convenience sampling of 99 patients, aged at least 18 years old, undergoing elective abdominal cancer surgeries, with anesthesia lasting at least one hour, with each patient having their temperature measured by all three methods. RESULTS: the intraclass correlation coefficient showed a low correlation between the measurements using the peripheral temporal thermometer and the central cutaneous (0.0324) and esophageal/nasopharyngeal (-0.138) thermometers. There was a high correlation (0.744) between the central thermometers evaluated. CONCLUSION: the data from the current study do not recommend using infrared temporal thermometers as a strategy for measuring the body temperature of patients undergoing anesthetic-surgical procedures. Central cutaneous thermometers and esophageal/nasopharyngeal thermometers are equivalent for detecting intraoperative hypothermia.

A SICE (Società Italiana di Chirurgia Endoscopica e Nuove Tecnologie) observational prospective multicenter study on anatomical variants of the superior mesenteric artery: intraoperative analysis during laparoscopic right hemicolectomy-CoDIG 2 database (ColonDx Italian Group).

Colorectal cancer, the third most common cancer worldwide, affects 40-45% of patients on the right side. Surgery, especially minimally invasive methods such as laparoscopic and robotic procedures, is the preferred treatment. However, these techniques present technical complications. The anatomical complexity and variations in vessel branching patterns pose challenges, particularly for less experienced surgeons. The CoDIG 2 is a nationwide observational study involving 76 specialized Italian general surgery departments focused on colorectal surgery. The centres were directed to maintain their standard surgical and clinical practices. The aim of this study was to analyse the intraoperative vascular anatomy of Italian patients who underwent laparoscopic right colectomy and explore the ligature techniques used by Italian surgeons. Surgeons reported information about vascularization of the right colon for 616 patients and about surgical anatomy of RCA for 368 patients. Fifty-three patients (10.8%) showed no RCA intraoperatively. The right colic artery (RCA) was categorized according to the Yada classification (types 1-4) during evaluation, and intraoperative assessments revealed that Yada type 1 was the most common type (55.2%), while radiologic evaluations revealed a higher prevalence of type 2. Furthermore, compared with the superior mesenteric vein (SMV), the RCA is more often located anteriorly according to intraoperative and contrast-enhanced CT examination; 59.9% were found in the anterior position during intraoperative examination, while 40.1% were found in the same position on preoperative contrast-enhanced CT. Vascularization of the right colon, including missing branches, additional branches, shared trunks, and retro-superior courses of the mesenteric vein, exhibited notable variations. To understand vascular variations, a preoperative radiological study is necessary; although there was no concordance between the intraoperative and radiological evaluations, this is a limitation of preinterventional radiological evaluation (PII) because it is always needed for oncological staging. This approach is especially critical for inexperienced surgeons to avoid potential complications, such as problematic bleeding.

Discrepancies Between Intraoperative and Postoperative Ankle Motion Measured for Anterior-Approach Total Ankle Arthroplasty.

BACKGROUND: Although intraoperative ankle motion serves as a foundational reference for anticipated motion after surgery and guides the addition of procedures to enhance ankle motion in total ankle arthroplasty (TAA), the relationship between intraoperative and postoperative ankle motion remains unclear. This study aimed to investigate the discrepancy between intraoperative and postoperative ankle range of motion (ROM) following TAAs using the anterior-approach, fixed-bearing systems. METHODS: This study retrospectively reviewed 67 patients (67 ankles) who underwent primary TAA at a single institution. Three different types of anterior-approach, fixed-bearing TAA systems were included. Intraoperative fluoroscopy was used to document the maximal dorsiflexion and plantar flexion at the end of the case. Standardized weightbearing maximum dorsiflexion and plantar flexion sagittal radiographs were obtained pre- and postoperatively, following a previously described method. The motion between 3 different time points (preoperative, intraoperative, and postoperative [mean 11.4 months]) was compared using pairwise t tests, and their differences were quantified. RESULTS: The mean total tibiotalar ROM was 38.1 degrees (SD 7.8) intraoperatively, and the postoperative total tibiotalar ROM was 24.2 degrees (SD 9.7) (P < .001), indicating that a mean of 65.3% (SD 26.7) of the intraoperative motion was maintained postoperatively. Intraoperative dorsiflexion (mean 11.6 [SD 4.5] degrees) showed no evidence of difference from postoperative dorsiflexion (mean 11.4 [SD 5.8] degrees, P > .99), indicating that a median of 95.6% (interquartile range: 66.2-112) of the intraoperative maximum dorsiflexion was maintained postoperatively. However, there was a significant difference between intraoperative plantarflexion (mean 26.4 [SD 6.3]) and postoperative plantarflexion (12.8 [SD 6.9] degrees, P < .001), indicating a mean 50.6% (SD 29.6) of intraoperative motion maintained in the postoperative assessment. There was an improvement of 2.5 degrees in the total tibiotalar ROM following TAA with statistical significance (P < .043). CONCLUSION: This study revealed a significant difference between intraoperative ankle ROM and ankle ROM approximately 1 year after anterior-approach, fixed-bearing TAA, mainly due to plantarflexion motion restriction. Minimal difference in dorsiflexion suggests the importance of achieving the desired postoperative dorsiflexion motion during the surgery using the best possible adjunct procedures. LEVEL OF EVIDENCE: Level IV, case series.

Advancing Intraoperative Assessment of Urethral Stricture Anatomic Variation: A Prospective Proof-of-Concept Study.

INTRODUCTION: Urethral strictures, particularly those refractory to endoscopic interventions, are commonly treated through open urethroplasty. However, predicting recurrence in homogeneous patient populations remains challenging. METHODS: To address this, we developed an intraoperative urethral stricture assessment tool aiming to identify comprehensive risk predictors. The assessment includes detailed parameters on stricture location, length, urethral bed width, spongiosum thickness, obliteration grade, and spongiofibrosis extension. The tool was prospectively implemented in 106 men with anterior one-stage augmentation urethroplasty from April 2020 to October 2021. RESULTS: An intraoperative granular assessment of intricate stricture characteristics is feasible. Comparative analyses revealed significant differences between bulbar and penile strictures. Bulbar strictures exhibited wider urethral beds and thicker spongiosum compared to penile strictures (all p < 0.001). The assessment showed marked variations in the degree of obliteration and spongiofibrosis extension. CONCLUSION: Our tool aligns with efforts to standardize urethral surgery, providing insights into subtle disease intricacies and enabling comparisons between institutions. Notably, intraoperative assessment may surpass the limitations of preoperative imaging, emphasizing the necessity of intraoperative evaluation. While limitations include a single-institution study and limited sample size, future research aims to refine this tool and determine its impact on treatment strategies, potentially improving long-term outcomes for urethral strictures.

Intraoperative Regional Cerebral Oxygenation During Pediatric Thoracoscopic Surgery: A Systematic Review.

Background: Ventilating a pediatric patient during thoracoscopy is challenging. Few studies have highlighted the impact of capnothorax in children by measuring regional cerebral oxygen saturation (rcSO2) with near infrared spectroscopy. In this systematic review, we aimed to summarize the data from relevant studies and assess whether thoracoscopy in children is associated with intraoperative pathological cerebral desaturation. Methods: The authors systematically searched four databases for relevant studies on the measurement of rcSO2 during pediatric thoracoscopic procedures. The primary outcome was the proportion of patients with pathological desaturation, that is, >20% decline in the intraoperative rcSO2. Risk of bias among the included studies was estimated using the Newcastle-Ottawa scale. Results: The systematic search resulted in 776 articles, of which 7 studies were included in the analysis. In total, 88 patients (99 procedures) with an age ranging from 0 days to 8.1 years were included. Of these, 43 (49%) patients were neonates. The included cohort had esophageal atresia and tracheoesophageal fistula (n = 26), long-gap esophageal atresia (n = 5), congenital diaphragmatic hernia (n = 14), and congenital pulmonary airway malformations and other conditions needing lung resection (n = 43). Of the total 99 procedures, pathological desaturation was noticed in 13 (13.1%, 95% confidence interval 7.2-21.4) of them. Upon quality assessment, most of the studies were weaker in the selection and comparability domains. Conclusion: In this review, pathological cerebral desaturation was noticed in 13.1% of the pediatric thoracoscopic procedures. However, due to limited methodological quality of the included studies, further randomized multicentric studies comparing rcSO2 in open versus thoracoscopic surgeries are needed to derive definitive conclusions.

Appropriate concentration setting for the intraoperative administration of indocyanine green for fluorescence imaging to identify the sentinel lymph node in early gastric cancer: a clinical pilot study.

PURPOSE: Some prospective trials have demonstrated the feasibility of sentinel node (SN) biopsy in gastric cancer (GC) surgery. This study aimed to identify the appropriate concentration settings for the intraoperative injection of indocyanine green (ICG) for SN biopsy. METHODS: Before the clinical studies, porcine model experiments explored the optimal concentration of ICG injected intraoperatively. Next, nine GC patients were enrolled in the clinical research. ICG (0.5 ml) was injected intraoperatively into four quadrants of the submucosa around the tumor at various concentrations (0.5, 0.25, and 0.1 mg/ml). The lymphatic basin dissection method was applied to the ICG-positive lymphatic areas. The number and location of the lymphatic basins and positive nodes were recorded intraoperatively. RESULTS: In the porcine model, the visibility gradually became clear at an ICG concentration higher than 0.1 mg/ml. In the clinical study, the average number of detected lymphatic basins was 3.3, 1.7, and 1.7, respectively. The mean number of detected SNs was 14.7, 6.7, and 4.0, respectively. CONCLUSION: To improve the reproducibility of SN biopsy, it is essential to prepare the correct concentration setting of ICG. Under current conditions in which ICG is injected intraoperatively, a 0.1 mg/ml concentration setting of ICG may be necessary and sufficient for SN identification.

A prospective comparison of a modified miniaturised hand-held epifluorescence microscope and touch imprint cytology for evaluation of axillary sentinel lymph nodes intraoperatively in breast cancer patients.

BACKGROUND: The management of axillary lymph nodes in early-stage breast cancer patients has changed considerably, with the primary focus shifting from the examination of sentinel lymph nodes (SLNs) to toward the detection of all macro-metastases. However, current methods, such as touch imprint cytology (TIC) and frozen sections, are inadequate for clinical needs. To address this issue, we proposed a novel miniaturised epifluorescence widefield microscope (MEW-M) to assess SLN status intraoperatively for improved diagnostic efficiency. METHODS: A prospective, side-by-side comparison of intraoperative SLN evaluation between MEW-M and TIC was performed. RESULTS: A total of 73 patients with 319 SLNs consecutive enrolled in this study. MEW-M showed significantly superior image quality compared to TIC (median score 3.1 vs 2.1, p < 0.0001) and had a shorter time to issue results (10.3 vs 19.4 min, p < 0.0001). Likelihood ratio analysis illustrated that the positive likelihood ratio value of MEW-M compared with TIC was infinitely great vs 52.37 (95% CI, 21.96-124.90) in model 1 (classifying results into negative/positive), infinitely great vs 52.37 (95% CI, 21.96-124.90) in model 2 (classifying results into macro-metastasis/others, and TIC results followed the same classification as model 1), respectively. Similarly, the negative likelihood ratio values of MEW-M compared with TIC were 0.055 (95% CI, 0.018-0.160) and 0.074 (95% CI, 0.029-0.190) in model 1; and 0.019 (95% CI, 0.003-0.130) vs 0.020 (95% CI, 0.003-0.140) in model 2, respectively. CONCLUSIONS: MEW-M is a promising technique that can be utilised to provide a rapid and accurate intraoperative assessment of SLN in a clinical setting to help improve decision-making in axillary surgery.

Assessment of the need for routine intraoperative cell salvage in liver transplantation.

PURPOSE: This study aimed to assess the necessity of routine intraoperative cell salvage in liver transplantations. METHODS: A total of 327 liver transplants performed between 2014 and 2016 was included in the analysis. Patient data, including pre-transplant examinations, intraoperative red blood cell transfusions, and procedural information, were collected. RESULTS: The median age of the patients was 54 years old, with 67% (219) being male. The most prevalent ABO blood type was O, accounting for 48% (155) of cases. The leading causes of liver disease were hepatitis C (113 cases, 34.6%) and alcohol-related liver disease (97 cases, 29.7%). Out of the 327 liver transplants, allogeneic red blood cell transfusions were administered in 110 cases (34%) with a median of two units of red blood cells per case. Cell salvage was employed in 237 transplants (73%), and successful blood recovery was achieved in 221 cases (93%). Among the group that recovered more than 200 mL of blood, the median volume of recovered blood was 417 mL, with no transfusion of allogeneic blood required. A total of 90 transplants was performed without utilizing cell salvage, and, among these cases, 19 required blood transfusions, with a median of zero units transfused. CONCLUSIONS: This study suggests that routine cell salvage is unnecessary for all liver transplantations. The most suitable indication for its use is in patients presenting with portal vein thrombosis and abnormal creatinine levels.

First clinical application of image-guided intraoperative electron radiation therapy with real time intraoperative dose calculation in recurrent rectal cancer: technical procedure.

Intraoperative radiation therapy (IORT) is a radiation technique applying a single fraction with a high dose during surgery. We report the first abdomino-pelvic application of an image-guided intraoperative electron radiation therapy with intraoperative real time dose calculation based on the individual intraoperative patient anatomy. A patient suffering from locoregionally recurrent rectal cancer after treatment with neoadjuvant re-chemoradiation was chosen for this approach. After surgical removal of the recurrence, an adequate IORT applicator was placed as usual. A novel mobile imaging device (ImagingRing, MedPhoton) was positioned around the patient covering the region to be treated with the IORT-applicator in place. It allowed the acquisition of three-dimensional intraoperative cone-beam computed tomography images suitable for dose calculation using an automated scaling (heuristic object and head scatter as well as hardening corrections) of Hounsfield units. After image acquisition confirmed the correct applicator position, the images were transferred to our treatment planning system for intraoperative dose calculation. Treatment could be accomplished using the calculated dose distribution. We herein describe the details of the procedure including necessary adjustments in the typically used IORT equipment and work flow. We further discuss the pros and cons of this new approach generally overcoming a decade long limitation of IORT procedures as well as future perspectives regarding IORT treatments.

Role of intraoperative touch imprint cytology and immunohistochemistry in the diagnosis of metastatic malignancies in the central nervous system: Cyto-histomorphological findings and differential diagnosis.

BACKGROUND: Brain metastases (BMs) are intracranial neoplasms that are more common in adults than primary brain tumors, causing significant mortality and morbidity in cancer patients. This study aimed to evaluate the definitive histopathological diagnosis using touch imprint cytology and the importance and use of immunohistochemistry in the diagnosis of primary origin. METHOD: Cytological, paraffin section, and immunohistochemical study slides of all metastatic brain tumors consecutively consulted at the pathology department between 2018 and 2023 were evaluated. The sensitivity, specificity, and accuracy of patients' diagnostic results who underwent imprint cytology were compared based on the final diagnosis histopathological report. RESULTS: A total of 45 patients with and without intraoperative consultation were included in the study. The definitive histopathologic diagnosis and the diagnostic accuracy rate of imprint cytology for distinguishing glial and metastatic tumors on paraffin sections was 100%. Immunohistochemistry was performed in all patients (except one patient; immediate exitus) and histological classification of the primary tumor was performed by analysis of clinical findings and biomarkers. The primary origins of metastatic tumors were often lung and breast, with adenocarcinoma subtype histomorphology, cerebral hemispheres, and discrete foci of metastasis. CONCLUSION: TPs is a simple and rapid technique that supports diagnosis in intraoperative neuropathology and is a very cost-effective procedure. The pathologist's experience is the key factor in the diagnosis and reduces the need for a frozen section. In our series, the final histopathologic correlation of imprint cytology in the diagnosis of primary and metastatic tumors is 100%.

Intraoperative assessment of resection margins by Raman spectroscopy to guide oral cancer surgery.

Patients with oral cavity cancer are almost always treated with surgery. The goal is to remove the tumor with a margin of more than 5 mm of surrounding healthy tissue. Unfortunately, this is only achieved in about 15% to 26% of cases. Intraoperative assessment of tumor resection margins (IOARM) can dramatically improve surgical results. However, current methods are laborious, subjective, and logistically demanding. This hinders broad adoption of IOARM, to the detriment of patients. Here we present the development and validation of a high-wavenumber Raman spectroscopic technology, for quick and objective intraoperative measurement of resection margins on fresh specimens. It employs a thin fiber-optic needle probe, which is inserted into the tissue, to measure the distance between a resection surface and the tumor. A tissue classification model was developed to discriminate oral cavity squamous cell carcinoma (OCSCC) from healthy oral tissue, with a sensitivity of 0.85 and a specificity of 0.92. The tissue classification model was then used to develop a margin length prediction model, showing a mean difference between margin length predicted by Raman spectroscopy and histopathology of -0.17 mm.