Radiofrequency Identification Track for Tray Optimization: An Instrument Utilization Pilot Study in Surgical Oncology.

BACKGROUND: Surgical instrument tray reduction attempts to minimize intraoperative inefficiency and processing costs. Previous reduction methods relied on trained observers manually recording instrument use (i.e. human ethnography), and surgeon and/or staff recall, which are imprecise and inherently limited. We aimed to determine the feasibility of radiofrequency identification (RFID)-based intraoperative instrument tracking as an effective means of instrument reduction. METHODS: Instrument trays were tagged with unique RFID tags. A RFID reader tracked instruments passing near RFID antennas during 15 breast operations performed by a single surgeon; ethnography was performed concurrently. Instruments without recorded use were eliminated, and 10 additional cases were performed utilizing the reduced tray. Logistic regression was used to estimate odds of instrument use across cases. Cohen's Kappa estimated agreement between RFID and ethnography. RESULTS: Over 15 cases, 37 unique instruments were used (median 23 instruments/case). A mean 0.64 (median = 0, range = 0-3) new instruments were added per case; odds of instrument use did not change between cases (OR = 1.02, 95%CI 1.00-1.05). Over 15 cases, all instruments marked as used by ethnography were recorded by RFID tracking; 7 RFID-tracked instruments were never recorded by ethnography. Tray size was reduced 40%. None of the 25 eliminated instruments were required in 10 subsequent cases. Cohen's Kappa comparing RFID data and ethnography over all cases was 0.82 (95%CI 0.79-0.86), indicating near perfect agreement between methodologies. CONCLUSIONS: Intraoperative RFID instrument tracking is a feasible, data-driven method for surgical tray reduction. Overall, RFID tracking represents a scalable, systematic, and efficient method of optimizing instrument supply across procedures.

Automating neurosurgical tumor resection surgery: Volumetric laser ablation of cadaveric porcine brain with integrated surface mapping.

OBJECTIVE: Current surgical instruments for soft tissue resection including neurosurgical procedures rely on the accuracy and precision of the human operator and are fundamentally constrained by the human hand. Automated surgical action with the integration of intraoperative data sources can enable highly accurate and fast tissue manipulation using laser ablation. This study presents the first experiments with a prototype designed for automated tumor resection via laser ablation. We demonstrate targeted soft tissue resection in porcine brain with an integrated device that combines 3D scanning capabilities with a steerable surgical laser and discuss implications for future automated robotic neurosurgical procedures. STUDY DESIGN AND METHODS: A device consisting of a two-axis galvanometer for steering a cutting laser and a 3D surface profiler is used to perform volumetric removal of tissue of ex vivo porcine brain. Three-dimensional surface profiles are gathered between cuts and used to estimate ablation rate. RESULTS: Volumetric ablation of porcine brain tissue is performed and subsequently surface profiled. The average ablation rates across the area cutting areas were 2.6 mm3 /s and 3.7 mm3 /s for the initial and subsequent cuts, respectively. A Kruskal-Wallis and post-hoc Tukey test show statistical significance between the initial and subsequent cuts. Accuracy between cuts when benchmarked against a human surgeon varied from 47 to 88%. CONCLUSION: A feed-forward volumetric resection is demonstrated with sensing and cutting housed within a single device, thereby opening the potential for automated soft tissue resection as necessary during the surgical removal of pathologic tissues. High variance around target cut depths motivates future work in developing a closed-loop ablation tool as well as characterization of laser-tissue interactions for predictive modelling. Objective Lasers Surg. 50:1017-1024, 2018. © 2018 Wiley Periodicals, Inc.

Ablation of porcine ligamentum flavum with Ho:YAG, q-switched Ho:YAG, and quadrupled Nd:YAG lasers.

BACKGROUND AND OBJECTIVES: Ligamentum flavum (LF) is a tough, rubbery connective tissue providing a portion of the ligamentous stability to the spinal column, and in its hypertrophied state forms a significant compressive pathology in degenerative spinal stenosis. The interaction of lasers and this biological tissue have not been thoroughly studied. Technological advances improving endoscopic surgical access to the spinal canal makes selective removal of LF using small, flexible tools such as laser-coupled fiber optics increasingly attractive for treatment of debilitating spinal stenosis. Testing was performed to assess the effect of Ho:YAG, Q-switched Ho:YAG, and frequency quadrupled Nd:YAG lasers on samples of porcine LF. The objective was to evaluate the suitability of these lasers for surgical removal of LF. STUDY DESIGN/MATERIALS AND METHODS: LF was resected from porcine spine within 2 hours of sacrifice and stored in saline until immediately prior to laser irradiation, which occurred within an additional 2 hours. The optical absorbance of a sample was measured over the spectral band from 190 to 2,360 nm both before and after dehydration. For the experiments using the Ho:YAG (λ = 2,080 nm, tp = 140 µs, FWHM) and Q-Switched Ho:YAG (λ = 2,080 nm, tp = 260 ns, FWHM) lasers, energy was delivered to the LF through a laser-fiber optic with 600 µm core and NA = 0.39. For the experiment using the frequency quadrupled Nd:YAG laser (λ = 266 nm, tp = 5 ns FWHM), rather than applying the laser energy through a laser-fiber, the energy was focused through an aperture and lens directly onto the LF. Five experiments were conducted to evaluate the effect of the given lasers on LF. First, using the Ho:YAG laser, the single-pulse laser-hole depth versus laser fluence was measured with the laser-fiber in direct contact with the LF (1 g force) and with a standoff distance of 1 mm between the laser-fiber face and the LF. Second, with the LF remaining in situ and the spine bisected along the coronal plane, the surface temperature of the LF was measured with an IR camera during irradiation with the Ho:YAG laser, with and without constant saline flush. Third, the mass loss was measured over the course of 450 Ho:YAG pulses. Fourth, hole depth and temperature were measured over 30 pulses of fixed fluence from the Ho:YAG and Q-Switched Ho:YAG lasers. Fifth, the ablation rate and surface temperature were measured as a function of fluence from the Nd:YAG laser. Several LF staining and hole-depth measurement techniques were also explored. RESULTS: Aside from the expected absorbance peaks corresponding to the water in the LF, the most significant peaks in absorbance were located in the spectral band from 190 to 290 nm and persisted after the tissue was dehydrated. In the first experiment, using the Ho:YAG laser and with the laser-fiber in direct contact with the LF, the lowest single-pulse fluence for which LF was visibly removed was 35 J/cm(2) . Testing was conducted at 6 fluences between 35 and 354 J/cm(2) . Over this range the single-pulse hole depth was shown to be near linear (R(2) = 0.9374, M = 1.6), ranging from 40 to 639 µm (N = 3). For the case where the laser-fiber face was displaced 1 mm from the LF surface, the lowest single-pulse fluence for which tissue was visibly removed was 72 J/cm(2) . Testing was conducted at 4 energy densities between 72 and 180 J/cm(2) . Over this range the single-pulse hole depth was shown to be near linear (R(2) = 0.8951, M = 1.4), ranging from 31 to 220 µm (N = 3). In the second experiment, with LF in situ, constant flushing with room temperature saline was shown to drastically reduce surface temperature during exposure to Ho:YAG at 5 Hz with the laser-fiber in direct contact with the LF. Without saline, over 1 minute of treatment with a per-pulse fluence of 141 mJ/cm(2) , the average maximum surface temperature measured 110°C. With 10 cc's of saline flushed over 1 minute and a per-pulse laser fluence of 212 mJ/cm(2) , the average maximum surface temperature was 35°C. In the third experiment, mass loss was shown to be linear over 450 pulses of 600 mJ from the Ho:YAG laser (212 J/cm(2) , direct contact, N = 4; 108 J/cm(2) , 1 mm standoff, N = 4). With the laser-fiber in direct contact, an average of 53 mg was removed (R(2) = 0.996, M = 0.117) and with 1 mm laser-fiber standoff, an average of 44 mg was removed (R(2) = 0.9988, M = 0.097). In the fourth experiment, 30 pulses of the Ho:YAG and Q-Switched Ho:YAG lasers at 1 mm standoff, and 5 Hz produced similar hole depths for the tested fluences of 9 J/cm(2) (151 and 154 µm, respectively) and 18 J/cm(2) (470 and 442 µm, respectively), though the Ho:YAG laser produced significantly more carbonization around the rim of the laser-hole. The increased carbonization was corroborated by higher measured LF temperature. In all tests with the Ho:YAG and Q-Switched Ho:YAG, an audible photo-acoustic affect coincided with the laser pulse. In the fifth experiment, with the frequency quadrupled Nd:YAG laser at 15 Hz for 450 pulses, ablation depth per pulse was shown to be linear for the fluence range of 0.18 - 0.73 J/cm(2) (R(2) = 0.989, M = 2.4). There was no noticeable photo-acoustic effect nor charring around the rim of the laser-hole. CONCLUSION: The Ho:YAG, Q-Switched Ho:YAG, and frequency quadrupled Nd:YAG lasers were shown to remove ligamentum flavum (LF). A single pulse of the Ho:YAG laser was shown to cause tearing of the tissue and a large zone of necrosis surrounding the laser-hole. Multiple pulses of the Ho:YAG and Q-Switched Ho:YAG lasers caused charring around the rim of the laser-hole, though the extent of charring was more extensive with the Ho:YAG laser. Charring caused by the Ho:YAG laser was shown to be mitigated by continuously flushing the affected LF with saline during irradiation. The Nd:YAG laser was shown to ablate LF with no gross visible indication of thermal damage to surrounding LF.

Concentric Tube Robot Design and Optimization Based on Task and Anatomical Constraints.

Concentric tube robots are catheter-sized continuum robots that are well suited for minimally invasive surgery inside confined body cavities. These robots are constructed from sets of pre-curved superelastic tubes and are capable of assuming complex 3D curves. The family of 3D curves that the robot can assume depends on the number, curvatures, lengths and stiffnesses of the tubes in its tube set. The robot design problem involves solving for a tube set that will produce the family of curves necessary to perform a surgical procedure. At a minimum, these curves must enable the robot to smoothly extend into the body and to manipulate tools over the desired surgical workspace while respecting anatomical constraints. This paper introduces an optimization framework that utilizes procedureor patient-specific image-based anatomical models along with surgical workspace requirements to generate robot tube set designs. The algorithm searches for designs that minimize robot length and curvature and for which all paths required for the procedure consist of stable robot configurations. Two mechanics-based kinematic models are used. Initial designs are sought using a model assuming torsional rigidity. These designs are then refined using a torsionally-compliant model. The approach is illustrated with clinically relevant examples from neurosurgery and intracardiac surgery.

Machine learning approaches in non-contact autofluorescence spectrum classification.

Manual surgical resection of soft tissue sarcoma tissue can involve many challenges, including the critical need for precise determination of tumor boundary with normal tissue and limitations of current surgical instrumentation, in addition to standard risks of infection or tissue healing difficulty. Substantial research has been conducted in the biomedical sensing landscape for development of non-human contact sensing devices. One such point-of-care platform, previously devised by our group, utilizes autofluorescence-based spectroscopic signatures to highlight important physiological differences in tumorous and healthy tissue. The following study builds on this work, implementing classification algorithms, including Artificial Neural Network, Support Vector Machine, Logistic Regression, and K-Nearest Neighbors, to diagnose freshly resected murine tissue as sarcoma or healthy. Classification accuracies of over 93% are achieved with Logistic Regression, and Area Under the Curve scores over 94% are achieved with Support Vector Machines, delineating a clear way to automate photonic diagnosis of ambiguous tissue in assistance of surgeons. These interpretable algorithms can also be linked to important physiological diagnostic indicators, unlike the black-box ANN architecture. This is the first known study to use machine learning to interpret data from a non-contact autofluorescence sensing device on sarcoma tissue, and has direct applications in rapid intraoperative sensing.

A blinded study using laser induced endogenous fluorescence spectroscopy to differentiate ex vivo spine tumor, healthy muscle, and healthy bone.

Ten patients undergoing surgical resection for spinal tumors were selected. Samples of tumor, muscle, and bone were resected, de-identified by the treating surgeon, and then scanned with the TumorID technology ex vivo. This study investigates whether TumorID technology is able to differentiate three different human clinical fresh tissue specimens: spine tumor, normal muscle, and normal bone. The TumorID technology utilizes a 405 nm excitation laser to target endogenous fluorophores, thereby allowing for the detection of tissue based on emission spectra. Metabolic profiles of tumor and healthy tissue vary, namely NADH (bound and free emission peak, respectively: 487 nm, 501 nm) and FAD (emission peak: 544) are endogenous fluorophores with distinct concentrations in tumor and healthy tissue. Emission spectra analyzed consisted of 74 scans of spine tumor, 150 scans of healthy normal bone, and 111 scans of healthy normal muscle. An excitation wavelength of 405 nm was used to obtain emission spectra from tissue as previously described. Emission spectra consisted of approximately 1400 wavelength intensity pairs between 450 and 750 nm. Kruskal-Wallis tests were conducted comparing AUC distributions for each treatment group, α = 0.05. Spectral signatures varied amongst the three different tissue types. All pairwise comparisons among tissues for Free NADH were statistically significant (Tumor vs. Muscle: p = 0.0006, Tumor vs. Bone: p < 0.0001, Bone vs. Muscle: p = 0.0357). The overall comparison of tissues for FAD (506.5-581.5 nm) was also statistically significant (p < 0.0001), with two pairwise comparisons being statistically significant (Tumor vs. Muscle: p < 0.0001, Tumor vs. Bone: p = 0.0045, Bone vs. Muscle: p = 0.249). These statistically significant differences were maintained when stratifying tumor into metastatic carcinoma (N = 57) and meningioma (N = 17). TumorID differentiates tumor tissue from normal bone and normal muscle providing further clinical evidence of its efficacy as a tissue identification tool. Future studies should evaluate TumorID's ability to serve as an adjunctive tool for intraoperative assessment of surgical margins and surgical decision-making.

N-mirror Robot System for Laser Surgery: A Simulation Study.

Automated laser surgery with sensor fusion is an important problem in medical robotics since it requires precise control of mirrors used to steer the laser systems. The propagation of the laser beam should satisfy the geometric constraints of the surgical site but the relation between the number of mirrors and the design of the optical path remains an unsolved problem. Furthermore, different types of surgery (e.g. endoscopic vs open surgery) can require different optical designs with varying number of mirrors to successfully steer the laser beam to the tissue. A generalized method for controlling the laser beam in such systems remains an open research question. This paper proposes an analytical model for a laser-based surgical system with an arbitrary number of mirrors, which is referred as an "N-mirror" robotic system. This system consists of three laser inputs to transmit the laser beam to the tissue surface through N number of mirrors, which can achieve surface scanning, tissue resection and tissue classification separately. For sensor information alignment, the forward and inverse kinematics of the N-mirror robot system are derived and used to calculate the mirror angles for laser steering at the target surface. We propose a system calibration method to determine the laser input configuration that is required in the kinematic modelling. We conduct simulation experiments for a simulated 3-mirror system of an actual robotic laser platform and a 6-mirror simulated robot, both with 3-laser inputs. The simulation experiments for system calibration show results of maximum position offset smaller than 0.127 mm and maximum angle offset smaller than 0.05° for the optimal laser input predictions.

Use of Tympanostomy T-Tube for Endoscopic Endonasal Marsupialization of Small Rathke's Cleft Cysts: A Case Series.

Objectives This article describes a novel technique implementing the use of a tympanostomy t-tube to provide long-term marsupialization of small Rathke's cleft cysts (RCCs). Design A retrospective review of electronic medical records was performed to collect demographic and clinical data on a series of four patients. Setting Academic medical center. Participants Four female patients (mean age of 34 years) underwent transsphenoidal endoscopic endonasal surgery for RCC. All four patients presented with headaches. Mean cyst size was 7 mm. Two of the four surgeries were revisions for RCC recurrence. Main Outcome Measures Symptom resolution after surgery, duration of follow-up, and feasibility of the proposed technique. Results Tympanostomy t-tube was used to marsupialize small RCCs (< 10 mm) for four patients. Three patients remained symptom-free with endoscopy and imaging showing patent t-tubes at 21 months' (range 20-24 months) follow-up. One patient experienced severe migraines immediately after surgery. Migraines were relieved after t-tube was removed 6 weeks after surgery. Conclusion Tympanostomy t-tubes placed via an endoscopic endonasal approach can provide long-term marsupialization for small RCCs.

Brain-Mimicking Phantom for Photoablation and Visualization.

While the use of tissue-mimicking (TM) phantoms has been ubiquitous in surgical robotics, the translation of technology from laboratory experiments to equivalent intraoperative tissue conditions has been a challenge. The increasing use of lasers for surgical tumor resection has introduced the need to develop a modular, low-cost, functionally relevant TM phantom to model the complex laser-tissue interaction. In this paper, a TM phantom with mechanically and thermally similar properties as human brain tissue suited for photoablation studies and subsequent visualization is developed. The proposed study demonstrates the tuned phantom response to laser ablation for fixed laser power, time, and angle. Additionally, the ablated crater profile is visualized using optical coherence tomography (OCT), enabling high-resolution surface profile generation.

Preoperative validation of edema-corrected tractography in neurosurgical practice: translating surgeon insights into novel software implementation.

Background: Peritumoral edema alters diffusion anisotropy, resulting in false negatives in tractography reconstructions negatively impacting surgical decision-making. With supratotal resections tied to survival benefit in glioma patients, advanced diffusion modeling is critical to visualize fibers within the peritumoral zone to prevent eloquent fiber transection thereafter. A preoperative assessment paradigm is therefore warranted to systematically evaluate multi-subject tractograms along clinically meaningful parameters. We propose a novel noninvasive surgically-focused survey to evaluate the benefits of a tractography algorithm for preoperative planning, subsequently applied to Synaptive Medical's free-water correction algorithm developed for clinically feasible single-shell DTI data. Methods: Ten neurosurgeons participated in the study and were presented with patient datasets containing histological lesions of varying degrees of edema. They were asked to compare standard (uncorrected) tractography reconstructions overlaid onto anatomical images with enhanced (corrected) reconstructions. The raters assessed the datasets in terms of overall data quality, tract alteration patterns, and the impact of the correction on lesion definition, brain-tumor interface, and optimal surgical pathway. Inter-rater reliability coefficients were calculated, and statistical comparisons were made. Results: Standard tractography was perceived as problematic in areas proximal to the lesion, presenting with significant tract reduction that challenged assessment of the brain-tumor interface and of tract infiltration. With correction applied, significant reduction in false negatives were reported along with additional insight into tract infiltration. Significant positive correlations were shown between favorable responses to the correction algorithm and the lesion-to-edema ratio, such that the correction offered further clarification in increasingly edematous and malignant lesions. Lastly, the correction was perceived to introduce false tracts in CSF spaces and - to a lesser degree - the grey-white matter interface, highlighting the need for noise mitigation. As a result, the algorithm was modified by free-water-parameterizing the tractography dataset and introducing a novel adaptive thresholding tool for customizable correction guided by the surgeon's discretion. Conclusion: Here we translate surgeon insights into a clinically deployable software implementation capable of recovering peritumoral tracts in edematous zones while mitigating artifacts through the introduction of a novel and adaptive case-specific correction tool. Together, these advances maximize tractography's clinical potential to personalize surgical decisions when faced with complex pathologies.

Creation of Non-Contact Device for Use in Metastatic Melanoma Margin Identification in ex vivo Mouse Brain.

Because contemporary intraoperative tumor detection modalities, such as intraoperative MRI, are not ubiquitously available and can disrupt surgical workflow, there is an imperative for an accessible diagnostic device that can meet the surgeon's needs in identifying tissue types. The objective of this paper is to determine the efficacy of a novel non-contact tumor detection device for metastatic melanoma boundary identification in a tissue-mimicking phantom, evaluate the identification of metastatic melanoma boundaries in ex vivo mouse brain tissue, and find the error associated with identifying this boundary. To validate the spatial and fluorescence resolution of the device, tissue-mimicking phantoms were created with modifiable optical properties. Phantom tissue provided ground truth measurements for fluorophore concentration differences with respect to spatial dimensions. Modeling metastatic disease, ex vivo melanoma brain metastases were evaluated to detect differences in fluorescence between healthy and neoplastic tissue. This analysis includes determining required-to-observe fluorescence differences in tissue. H&E staining confirmed tumor presence in mouse tissue samples. The device detected a difference in normalized average fluorescence intensity in all three phantoms. There were differences in fluorescence with the presence and absence of melanin. The estimated tumor boundary of all tissue phantoms was within 0.30 mm of the ground truth tumor boundary for all boundaries. Likewise, when applied to the melanoma-bearing brains from ex vivo mice, a difference in normalized fluorescence intensity was successfully detected. The potential prediction window for the tumor boundary location is less than 1.5 mm for all ex vivo mouse brain tumors boundaries. We present a non-contact, laser-induced fluorescence device that can identify tumor boundaries based on changes in laser-induced fluorescence emission intensity. The device can identify phantom ground truth tumor boundaries within 0.30 mm using instantaneous rate of change of normalized fluorescence emission intensity and can detect endogenous fluorescence differences in melanoma brain metastases in ex vivo mouse tissue.

Measuring intraoperative surgical instrument use with radio-frequency identification.

OBJECTIVE: Surgical instrument oversupply drives cost, confusion, and workload in the operating room. With an estimated 78%-87% of instruments being unused, many health systems have recognized the need for supply refinement. By manually recording instrument use and tasking surgeons to review instrument trays, previous quality improvement initiatives have achieved an average 52% reduction in supply. While demonstrating the degree of instrument oversupply, previous methods for identifying required instruments are qualitative, expensive, lack scalability and sustainability, and are prone to human error. In this work, we aim to develop and evaluate an automated system for measuring surgical instrument use. MATERIALS AND METHODS: We present the first system to our knowledge that automates the collection of real-time instrument use data with radio-frequency identification (RFID). Over 15 breast surgeries, 10 carpometacarpal (CMC) arthroplasties, and 4 craniotomies, instrument use was tracked by both a trained observer manually recording instrument use and the RFID system. RESULTS: The average Cohen's Kappa agreement between the system and the observer was 0.81 (near perfect agreement), and the system enabled a supply reduction of 50.8% in breast and orthopedic surgery. Over 10 monitored breast surgeries and 1 CMC arthroplasty with reduced trays, no eliminated instruments were requested, and both trays continue to be used as the supplied standard. Setup time in breast surgery decreased from 23 min to 17 min with the reduced supply. CONCLUSION: The RFID system presented herein achieves a novel data stream that enables accurate instrument supply optimization.

StereoCNC: A Stereovision-guided Robotic Laser System.

This paper proposes an End-to-End stereovision-guided laser surgery system that can conduct laser ablation on targets selected by human operators in the color image, referred as StereoCNC. Two digital cameras are integrated into a previously developed robotic laser system to add a color sensing modality and formulate the stereovision. A calibration method is implemented to register the coordinate frames between stereo cameras and the laser system, modelled as a 3D-to-3D least-squares problem. The calibration reprojection errors are used to characterize a 3D error field by Gaussian Process Regression (GPR). This error field can make predictions for new point cloud data to identify an optimal position with lower calibration errors. A stereovision-guided laser ablation pipeline is proposed to optimize the positioning of the surgical site within the error field, which is achieved with a Genetic Algorithm search; mechanical stages move the site to the low-error region. The pipeline is validated by the experiments on phantoms with color texture and various geometric shapes. The overall targeting accuracy of the system achieved an average RMSE of 0.13 ± 0.02 mm and maximum error of 0.34 ± 0.06 mm, as measured by pre- and post-laser ablation images. The results show potential applications of using the developed stereovision-guided robotic system for superficial laser surgery, including dermatologic applications or removal of exposed tumorous tissue in neurosurgery.

Touch-Point Detection Using Thermal Video With Applications to Prevent Indirect Virus Spread.

Viral and bacterial pathogens can be transmitted through direct contact with contaminated surfaces. Efficient decontamination of contaminated surfaces could lead to decreased disease transmission, if optimized methods for detecting contaminated surfaces can be developed. Here we describe such a method whereby thermal tracking technology is utilized to detect thermal signatures incurred by surfaces through direct contact. This is applicable in public places to assist with targeted sanitation and cleaning efforts to potentially reduce chance of disease transmission. In this study, we refer to the touched region of the surface as a "touch-point" and examine how the touch-point regions can be automatically localized with a computer vision pipeline of a thermal image sequence. The pipeline mainly comprises two components: a single-frame and a multi-frame analysis. The single-frame analysis consists of a Background subtraction method for image pre-processing and a U-net deep learning model for segmenting the touch-point regions. The multi-frame analysis performs a summation of the outputs from the single-frame analysis and creates a cumulative map of touch-points. Results show that the touch-point detection pipeline can achieve 75.0% precision and 81.5% F1-score for the testing experiments of predicting the touch-point regions. This preliminary study shows potential applications of preventing indirect pathogen spread in public spaces and improving the efficiency of cleaning sanitation.

Creation of an Automated Fluorescence Guided Tumor Ablation System.

OBJECTIVE: Create a device that improves the identification and extent of resection at the interface between healthy and tumor tissue; ultimately, using this device would improve surgical outcomes for patients and increase survival. METHODS: We have created a contactless tumor removal system that utilizes endogenous fluorescence feedback to inform a laser ablation system to execute autonomous removal of phantom tumor tissue. RESULTS: This completely non-contact surgical system is capable of resecting the tumor boundary of a tissue phantom with an average root mean square error (RMSE) of approximately 1.55 mm and an average max error of approximately 2.15 mm. There is no difference in the performance of the system when changing the size of the internal tumor from 7.5-12.5 mm in diameter. DISCUSSION: Future research steps include creating a more intelligent spectral search strategy to increase the density of points around the resection boundary, and to develop a more sophisticated classifier to predict pathologic diagnosis and tissue subtypes located regionally around the tumor boundaries. We envision this device being used to resect the boundaries of tumors identified by exogenously delivered tumor-labeling fluorophores, such as fluorescein or 5-ALA, in addition to approaches relying on autofluorescence of endogenous fluorophores.

Olfactory-Specific Quality of Life Outcomes after Endoscopic Endonasal Surgery of the Sella.

OBJECTIVE: To assess olfactory outcomes as measured by an olfactory-specific quality of life (QOL) questionnaire in patients undergoing EESBS for sellar lesions. DESIGN: Retrospective case series. SETTING: Tertiary academic medical center. PARTICIPANTS: In total, 36 patients undergoing EESBS for lesions limited to the sella were evaluated. MAIN OUTCOME MEASURES: The following were performed before and three months after surgery: 22-Item Sinonasal Outcomes Test (SNOT-22), University of Pennsylvania Smell Identification Test (UPSIT), and the Assessment of Self-reported Olfactory Functioning (ASOF), which has three domains: subjective olfactory capability scale (SOC), smell-related problems (SRP), and olfactory-related quality of life (ORQ). RESULTS: Median age at surgery was 52.5 years, with a median tumor size of 1.8 cm (range: 0.2 to 3.9 cm). Pre- and postoperative median scores were 35 [34, 36.2] and 34.5 [32, 36] for UPSIT, 21 [7.5, 33.5] and 21.5 [6.8, 35.7] for SNOT-22, 10 [9, 10] and 9 [8, 10] for ASOF-SOC, 5 [4.8, 5] and 4.5 [4, 5] for ASOF-SRP, and 5 [5, 5] and 5 [4.5, 5] for ASOF-ORQ. There was no significant change in the two of the three domains of the ASOF. Correlation between ASOF and UPSIT scores were weak. Older age and larger tumor size were associated with worsened olfaction after surgery. CONCLUSIONS: Patients did not experience significant changes in olfactory-specific QOL three months after EESBS, as measured by two domains of the ASOF. The ASOF may serve as a useful adjunctive tool for assessing olfaction after surgery. The lack of correlation between UPSIT and ASOF suggests the need for more research in subjective olfactory-related quality of life after surgery.

Targeting PD-L1 Initiates Effective Antitumor Immunity in a Murine Model of Cushing Disease.

PURPOSE: Although pituitary adenoma is classified as benign, Cushing disease is associated with significant morbidity due to the numerous sequelae of elevated cortisol levels. Successful therapy for Cushing disease remains elusive due to high rates of treatment-refractory recurrence. The frequent emergence of lymphocytic hypophysitis following checkpoint blockade for other cancers, as well as the expression of PD-L1 on pituitary adenomas, suggest a role for immunotherapy. EXPERIMENTAL DESIGN: This study confirms PD-L1 expression on functioning pituitary adenomas and is the first to evaluate the efficacy of checkpoint blockade (anti-PD-L1) therapy in a preclinical model of Cushing disease. RESULTS: Herein, treatment with anti-PD-L1 was successful in reducing adrenocorticotropic hormone plasma levels, decreasing tumor growth, and increasing survival in our model. Furthermore, tumor-infiltrating T cells demonstrated a pattern of checkpoint expression similar to other checkpoint blockade-susceptible tumors. CONCLUSIONS: This suggests that immunotherapy, particularly blockade of the PD1/PD-L1 axis, may be a novel therapeutic option for refractory Cushing disease. Clinical investigation is encouraged.

Two Extraordinary Sellar Neuronal Tumors: Literature Review and Comparison of Clinicopathologic Features.

Objectives: The list of tumors involving the pituitary gland has been expanded to include a variety of neuronal and paraneuronal tumors in the 2017 World Health Organization tumor classification of endocrine organs. All the entities included in this category are distinctly rare, with limited case reports in the literature. Methods: We illustrate two extraordinary sellar tumors with neuronal differentiation: a sellar paraganglioma and a sellar neurocytoma, with thorough literature review and comparison of the clinicopathologic features of these entities. Results: Both entities are exceptionally rare and tend to be misdiagnosed as pituitary adenoma preoperatively. Both entities demonstrate frequent clinical recurrence compared with pituitary adenoma, as well as the rare occurrence of metastatic disease. Conclusions: In evaluating a sellar tumor with an uncommon morphology and neuroendocrine differentiation, an increased awareness of the unusual entities that may involve the sellar region and a judicious panel of immunohistochemical studies should improve the diagnosis.

Novel Application of Steroid Eluting Stent in Petrous Apex Cholesterol Granuloma.

Objective This study describes the safety and efficacy of mometasone furoate eluting stents in the management of petrous apex cholesterol granuloma approached through an endonasal endoscopic route and assesses the restenosis rate. Methods Consecutive patients undergoing endoscopic endonasal marsupialization of a petrous apex cholesterol granuloma at a tertiary referral center who had a mometasone furoate eluting stent placed intraoperatively were reviewed in a retrospective fashion. Postoperative endoscopy was used to determine success of surgery and stenting. Results Five patients were included in the study, three were primary cases and two patients had revision surgeries performed. The steroid eluting stent was placed successfully and safely in all patients with no dural or vascular injuries. The average follow-up duration was 10.6 months. There was no restenosis in three patients and one patient had an immediate restenosis that was debrided in clinic (revision case). This was patent at the 16 months follow-up. One patient also developed stenosis, 4 months after surgery due to sphenoid sinusitis. Conclusion Mometasone furoate eluting stents are safe and effective in the primary management of petrous apex cholesterol granuloma. Further studies are needed to assess their efficacy in revision cases and for long term results.

Sinonasal Quality of Life Outcomes After Extended Endonasal Approaches to the Skull Base.

Introduction Endoscopic endonasal skull base surgery (EESBS) leads to significant alterations in sinonasal anatomy and physiology. However, there is limited data available on quality of life (QOL) outcomes following EESBS. Methods A retrospective review of patients undergoing EESBS from January 2014 to April 2017 was performed. Records were reviewed for clinical history, operative details, and 22-item Sinonasal Outcomes Test (SNOT-22) scores. Unadjusted and adjusted linear regression models were utilized to compare change in SNOT-22 scores from baseline in patients who underwent a simple sella approach (SA) or an extended beyond sella approach (BSA). Results A total of 108 patients were in the SA group, while 61 patients were in the BSA group. SNOT-22 scores were available at baseline and 3 months for 84 patients, while 6-month scores were available for 49 patients. SNOT-22 scores for all patients were not significantly different at 3 months ( p = 0.40) or at 6 months ( p = 0.58). Unadjusted linear regression model did not show an association between the type of approach and change in SNOT-22 score at 3 months ( p = 0.07) and 6 months ( p = 0.28). Adjusted regression model showed a significant decrease in SNOT-22 scores at 3 months ( p = 0.04) for the BSA group, but there was no significant change in SNOT-22 score at 6 months ( p = 0.22). Conclusion Patients undergoing EESBS had no significant change in outcomes at 3 and 6 months. A more extensive BSA was not associated with worse QOL outcomes as measured by SNOT-22.