Intraoperative Tool Research Articles

Towards Development of an Open Surgery Competency Assessment for Residents (OSCAR) Tool – A Systematic Review of the Literature and Delphi Consensus

Competency-based education has mandated accurate intra-operative assessment tools. We aimed to define consensus-based open surgical skills perceived by experts as critical for assessment. A mixed-method design was employed: systematic review and e-Delphi methodology. The study was performed at McGill University-affiliated large tertiary academic centers in Montreal, Quebec, Canada. Per PRISMA guidelines, a peer-reviewed search strategy was employed. Studies published in English and those describing technical skill assessment of open abdominal surgery were included; subspecialty-specific skills, conference abstracts, academic memoirs were excluded. Most-cited skills were subjected to e-Delphi methodology to identify those deemed essential by experts, based a 3-point Likert scale. Eighteen McGill University-affiliated general surgeons, representing a variety of subspecialties of General Surgery, were invited to answer the questionnaire. Around 120 of 4285 references were retained for analysis. The 12 most cited skills included suturing, tissue and instrument handling, movement economy, instrument knowledge, knot tying, flow, knowledge of procedure, completion time, dissection technique, knowledge of anatomy and sterile technique; 6 of these achieved high or perfect scores and agreement after 2 rounds of survey: suturing, sterile technique, knot tying, knowledge of anatomy, knowledge of procedure, and tissue handling. Median standard deviation decreased (0.495 to 0.450) from first to second round, indicating improvement in consensus. These results will help develop and validate the OSCAR (objective structured clinical assessment rubric) assessment tool for immediate intra-operative feedback of open technical skills for surgical trainees.

BOT-03 INVESTIGATION OF NOVEL SPRAY TYPE FLUORESCENT PROBE FOR GLIOBLASTOMA DETECTION

PURPOSE5-ALA is commonly used as an intraoperative tool in malignant glioma surgery, which has been proven effective for radical tumor resection and extended progression-free survival. However, there are some limitations in its use, such as false positivity, false negativity, and inability of re-administration. We aim to develop a novel fluorescent labeling system which can be repeatedly administered by spray during surgery, using hydroxymethyl rhodamine green (HMRG) as fluorescent scaffold originally designed at our university for cancer detection.METHODSPrimary probe screening was performed using the homogenized glioblastoma (GBM) samples with the fluorescent probe library comprised of more than 320 kinds of HMRG fluorescent scaffold combined with various types of dipeptides. Second probe screening was performed using fresh GBM specimens and the selected probes in primary screening. To identify the responsible enzymes, diced electrophoresis gel (DEG) assay was performed. This method utilizes the combination of two dimensional electrophoresis (isoelectric point and molecular weight) and a multiwell-plate-based fluorometric assay to find protein spots with the specified activities.RESULTSThe prominent probes were selected based upon the above two-step screenings. We identified two enzymes by proteome analysis and experiments using inhibitors, which was further confirmed with real-time PCR and western blotting.DISCUSSIONThis screening methodology is innovative in that it is based on selecting probes from the probe library that respond to clinical samples rather than creating probes from the responsible enzymes. Practical fluorescent probes can be established even for low-grade gliomas, which would be a breakthrough for rapid intraoperative diagnosis in glioma surgery.CONCLUSIONHMRG-based aminopeptidase fluorescent probes may be effective for GBM detection.

The approach of scratch-imprint cytology: Is it an alternative to frozen section for intraoperative assessment of pulmonary lesions?

To address the diagnostic performance of scratch-imprint cytology (SIC), in this study we compared intraoperative diagnoses of pulmonary lesions between SIC and frozen section histology (FSH) for accuracy with respect to the final pathological diagnosis. We histologically divided 206 pulmonary lesions (resected surgically) into two groups (benign and malignant) and compared each intraoperative diagnosis by SIC and FSH with the final pathological diagnoses. We also examined the radiological existence of pure ground-glass opacity (GGO) nodules in each group. The diagnostic sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 91.5%, 100%, 100%, 63.6%, and 92.6%, respectively for SIC, and 98.2%, 100%, 100%, 92.1% and 98.5%, respectively, for FSH. Thus, we concluded that diagnosis by SIC is reliable for malignancy, but not for benign lesions. All pure GGO nodules (19; 9.2%) were noninfectious and malignant with a high accuracy of FSH diagnosis (100%), in comparison with those of low accuracy with a SIC diagnosis (57.9%). SIC can be an appropriate intraoperative diagnostic tool where multiple cytotechnologists observe intraoperative SIC preparations scratched evenly across the whole lesion including the peripheral area of the mass.

Fluorescein-guided removal of peripheral nerve sheath tumors: a preliminary analysis of 20 cases.

Benign peripheral nerve sheath tumors (PNSTs) include mainly schwannomas-the most common tumors arising from peripheral nerves-and neurofibromas. Due to their origin, distinguishing between functional intact nerve and the fibers from whence the PNST arose may not always be easy to perform. The introduction of intraoperative tools to better visualize these tumors could be helpful in achieving a gross-total resection. In this study, the authors present a series of patients harboring PNST in which the surgery was performed under fluorescein guidance. Between September 2018 and February 2019, 20 consecutive patients with a total of 25 suspected PNSTs underwent fluorescein-guided surgery performed under microscopic view with a dedicated filter integrated into the surgical microscope (YELLOW 560) and with intraoperative monitoring. All patients presented with a different degree of contrast enhancement at preoperative MRI. Fluorescein was intravenously injected after intubation at a dose of 1 mg/kg. Preoperative clinical and radiological data, intraoperative fluorescein characteristics, and postoperative neurological and radiological outcomes were collected and analyzed. Six patients were affected by neurofibromatosis or schwannomatosis. There were 14 schwannomas, 8 neurofibromas, 1 myxoma, 1 reactive follicular hyperplasia, and 1 giant cell tumor of tendon sheath. No patient experienced worsening of neurological status after surgery. No side effects related to fluorescein injection were found in this series. Fluorescein allowed an optimal intraoperative distinction between tumor and surrounding nerves in 13 of 14 schwannomas and in all neurofibromas. In 6 neurofibromas and in 1 schwannoma, the final YELLOW 560 visualization showed the presence of small tumor remnants that were not visible under white-light illumination and that could be removed, obtaining a gross-total resection. Fluorescein was demonstrated to be a feasible, safe, and helpful intraoperative adjunct to better identify and distinguish PNSTs from intact functional nerves, with a possible impact on tumor resection, particularly in diffuse neurofibromas.

What Is in a Number? Evaluating a Risk Assessment Tool in Immediate Breast Reconstruction.

Patients undergoing immediate breast reconstruction were prospectively identified and evaluated with an intraoperative mastectomy flap ischemia risk assessment tool consisting of 8 binary questions. Breast measurements and patient demographics were recorded. Reconstructions were then prospectively evaluated postoperatively for ischemic complications. Outcomes were analyzed with significance set at P values <0.05. Thirty-one patients underwent 45 immediate breast reconstruction. The majority of reconstructions were tissue expander based (64.4%) following therapeutic (62.2%) skin-sparing (93.3%) mastectomies. Average follow-up was 11.16 months. Sixteen reconstructions (35.6%) experienced an ischemic complication. The average total mastectomy flap ischemic risk score was 4.29. The correlation value of higher scores with increasing ischemic complications was 0.65. Reconstructions with scores greater than 5 had significantly higher rates of ischemic complications (P = 0.0025). Reconstructions with a score of >6 and >7 also had significantly higher rates of ischemic complications (P < 0.0001, each). The sensitivity and specificity of intraoperative mastectomy flap compromise were 81.25% and 62.07%. Ischemic complications after immediate breast reconstruction were positively correlated with higher scores using a clinical intraoperative mastectomy flap ischemia risk assessment tool. Scores greater than 5 seem to be a threshold value at which ischemic complications are significantly greater. This simple, easy-to-implement intraoperative tool may assist plastic surgeons in assessing risk and optimizing outcomes in immediate breast reconstruction.

Feasibility evaluation of micro-optical coherence tomography (\u03bcOCT) for rapid brain tumor type and grade discriminations: \u03bcOCT images versus pathology

BackgroundPrecise identification, discrimination and assessment of central nervous system (CNS) tumors is of critical importance to brain neoplasm treatment. Due to the complexity and limited resolutions of the existing diagnostic tools, however, it is difficult to identify the tumors and their boundaries precisely in clinical practice, and thus, the conventional way of brain neoplasm treatment relies mainly on the experiences of neurosurgeons to make resection decisions in the surgery process. The purpose of this study is to explore the potential of Micro-optical coherence tomography (μOCT) as an intraoperative diagnostic imaging tool for identifying and discriminating glioma and meningioma with their microstructure imaging ex vivo, which thus may help neurosurgeons to perform precise surgery with low costs and reduced burdens.MethodsFresh glioma and meningioma samples were resected from patients, and then slices of such samples were excised and imaged instantly ex vivo with a lab-built μOCT, which achieves a spatial resolution of ~ 2.0 μm (μm). The acquired optical coherence tomography (OCT) images were pathologically evaluated and compared to their corresponding histology for both tumor type and tumor grade discriminations in different cases.ResultsBy using the lab-built μOCT, both the cross-sectional and en face images of glioma and meningioma were acquired ex vivo. Based upon the morphology results, both the glioma and meningioma types as well as the glioma grades were assessed and discriminated. Comparisons between OCT imaging results and histology showed that typical tissue microstructures of glioma and meningioma could be clearly identified and confirmed the type and grade discriminations with satisfactory accuracy.ConclusionsμOCT could provide high-resolution three-dimensional (3D) imaging of the glioma and meningioma tissue microstructures rapidly ex vivo. μOCT imaging results could help discriminate both tumor types and grades, which illustrates the potential of μOCT as an intraoperative diagnostic imaging tool to help neurosurgeons perform their surgery precisely in tumor treatment process.

Machine learning of physiological waveforms and electronic health record data to predict, diagnose and treat haemodynamic instability in surgical patients: protocol for a retrospective study

IntroductionAbout 42 million surgeries are performed annually in the USA. While the postoperative mortality is less than 2%, 12% of all patients in the high-risk surgery group account for 80%...

Brain tumour homogenates analysed by surface-enhanced Raman spectroscopy: Discrimination among healthy and cancer cells.

One of the biggest challenge for modern medicine is to make a discrimination among healthy and cancerous tissues. Therefore, nowadays big effort of scientist are devoted to find a new way for as fast as possible diagnosis with as much as possible accuracy in distinguishing healthy from cancerous tissues. That issues are probably the most important in the case of brain tumours, when the diagnosis time plays a great role. Herein we present the surface-enhanced Raman spectroscopy (SERS) together with the principal component analysis (PCA) used to identify the spectra of different brain specimens, healthy and tumour tissues homogenates. The presented analyses include three sets of brain tissues as control samples taken from healthy objects (one set consists of samples from four brain lobes and both hemispheres; eight samples) and the brain tumours from five patients (two Anaplastic Astrocytoma and three Glioblastoma samples). Results prove that tumour brain samples can be discriminated well from the healthy tissues by using only three main principal components, with 96% of accuracy. The largest influence onto the calculated separation is attributed to the spectral regions corresponding in SERS spectra to vibrations of the L-Tryptophan (1450, 1278cm-1), protein (1300cm-1), phenylalanine and Amide-I (1005, 1654cm-1). Therefore, the presented method may open the way for the probable application as a very fast diagnosis tool alternative for conventionally used histopathology or even more as an intraoperative diagnostic tool during brain tumour surgery.

DDIS-02. DEVELOPMENT OF NOVEL SPRAY-TYPE FLUORESCENT PROBES FOR GLIOBLASTOMA DETECTION

Abstract PURPOSE: ALA is commonly used as an intraoperative tool in malignant glioma surgery, which has been proven effective for radical tumor resection and extended progression-free survival. However, there are some limitations in its use, such as false positivity, false negativity, and inability of re-administration. We aim to develop a novel fluorescent labeling system which can be repeatedly administered by spray during surgery, using hydroxymethyl rhodamine green (HMRG) as fluorescent scaffold originally designed at our university for cancer detection. [Methods]Primary probe screening was performed using the homogenized glioblastoma (GBM) samples with the fluorescent probe library comprised of more than 320 kinds of HMRG fluorescent scaffold combined with various types of dipeptides. Second probe screening was performed using fresh GBM specimens and the selected probes in primary screening. To identify the responsible enzymes, diced electrophoresis gel (DEG) assay was performed. This method utilizes the combination of two dimensional electrophoresis (isoelectric point and molecular weight) and a multiwell-plate-based fluorometric assay to find protein spots with the specified activities. [Results] The prominent probes were selected based upon the above two-step screenings. We identified two enzymes by proteome analysis and experiments using inhibitors, which was further confirmed with real-time PCR and western blotting. [Discussion] This screening methodology is innovative in that it is based on selecting probes from the probe library that respond to clinical samples rather than creating probes from the responsible enzymes. Practical fluorescent probes can be established even for low-grade gliomas, which would be a breakthrough for rapid intraoperative diagnosis in glioma surgery. [Conclusion] HMRG-based aminopeptidase fluorescent probes may be effective for GBM detection.

SURG-20. IDENTIFICATION OF INFILTRATIVE CANCER CELLS AT THE GLIOMA RESECTION CAVITY MARGIN USING STIMULATED RAMAN SCATTERING MICROSCOPY

Abstract INTRODUCTION Microscopic residual disease at the tumor margin is the primary barrier to complete resection which impacts outcome. Stimulated Raman scattering microscopy (SRM) has proven effective to classify CNS tumor tissue and detect tumor cells within grossly normal post mortem glioma specimens. In this study, we use SRM for detection of residual glioma cells within the resection cavity margins. METHODS Patients with gliomas undergoing surgical resection were included. Margin samples were taken after the primary surgeon determined the resection cavity wall to be grossly normal and were analyzed using (1) true H&amp;E, (2) SRM pseudo H&amp;E, (3) immunohistochemical stains (IHC) for IDH1-R132H or p53. The sections were scored on a scale of 0–3 by a neuropathologist blinded to the corresponding results from each modality (0=no definite tumor cells; 1=rare tumor cells; 2=moderate tumor cells with preserved neuropil; 3 = abundant tumor cells). Positive and negative predictive values and Spearman correlation coefficients were calculated. RESULTS Ninety-one margin samples from 19 patients were included. Tumors were WHO grade II (29.7%), III (38.5%), and IV (31.8%). There was a strong correlation between SRM and H&amp;E (Spearman correlation (r) = 0.76), SRM and IHC (r=0.81), and H&amp;E and IHC scores (r=0.91). PPV of SRM score of 3 was 100%. The presence of tumor cells on SRM (scores 1–3) strongly correlated with the presence of tumor cells on H&amp;E (PPV = 95%) and IHC (PPV = 91%). The absence of tumor cells on SRM correlated with absence of tumor on H&amp;E and IHC only 10% and 50% (NPV) of the time, respectively. CONCLUSIONS The PPV of utilizing SRM to detect residual glioma cells in grossly normal resection cavity margins is high however the NPV is low. SRM may have utility as a rapid point-of-care intraoperative tool for identification of infiltrative glioma within resection cavity margins.

Evaluation of surgically excised breast tissue microstructure using wide-field optical coherence tomography.

Currently, positive margins at lumpectomy contribute to health care cost, patient anxiety, and treatment delay. Multiple technology solutions are being explored with the aim of lowering re-excision rates for breast-conserving surgery (BCS). We examined wide-field optical coherence tomography (WF-OCT), an innovative adjunct intraoperative imaging tool for tissue visualization of margins. This IRB-approved pilot study included women with invasive or in situ carcinoma scheduled for primary BCS. Lumpectomy specimens and any final/revised margins were imaged by optical coherence tomography immediately prior to standard histological processing. The optical coherence tomography used provided two-dimensional, cross-sectional, real-time depth visualization of the margin widths around excised specimens. A volume of images was captured for 10×10cm tissue surface at high resolution (sub-30μm) to a depth of 2mm. Integrated interpretation was performed incorporating final pathology linked with the optical image data for correlation. Wide-field optical coherence tomography was performed on 185 tissue samples (50 lumpectomy specimens and 135 additional margin shaves) in 50 subjects. Initial diagnosis was invasive ductal carcinoma (IDC) in 10, ductal carcinoma in situ (DCIS) in 14, IDC/DCIS in 22, invasive lobular carcinoma (ILC) in 2, ILC/DCIS in 1, and sarcoma in 1. Optical coherence tomography was concordant with final pathology in 178/185 tissue samples for overall accuracy of 86% and 96.2% (main specimen alone and main specimen+shave margins). Of seven samples that were discordant, 57% (4/7) were considered close (DCIS<2mm from margin) per final pathology. Wide-field optical coherence tomography demonstrated concordance with histology at tissue margins, supporting its potential for use as a real-time adjunct intraoperative imaging tool for margin assessment. Further studies are needed for comprehensive evaluation in the intraoperative setting.

Additive value of intraoperative hemodynamic monitoring to epicardial echocardiography during surgical repair of children with congenital heart disease

Aim The aim was to evaluate the additive value of intraoperative hemodynamic monitoring to epicardial echocardiography on the surgical outcome in children undergoing surgical correction of congenial heart disease. Patients and methods This study was conducted on 238 children with congenital heart disease who were enrolled for surgical correction. They were arranged in two groups: group A included 159 children in whom e-echo was used to detect intraoperative residual lesions while group B included 79 patients in whom e-echo and intraoperative hemodynamic monitoring using oxygen saturation step-up and intracardiac pressures after disconnection of cardiopulmonary bypass to detect residual shunt flow and outflow tract obstruction were used; revision of bypass was done when significant lesions were detected for repair. The follow-up echocardiography showed no significant residual lesions and complications in the subgroup of patients who had both epicardial monitoring and hemodynamic studies, in contrast to other groups of patients in whom19 patients had residual lesions and complications. Conclusions Routine use of intraoperative epicardial echocardiography allows detection of majority of residual defects after bypass; however, addition of other intraoperative monitoring tools like hemodynamic pressure measurement and oxygen saturation step-up can result in the detection of more residual lesions with revision of bypass, thus saving these patients from reoperation and postoperative complications.

Chromophore selective multi-wavelength photoacoustic remote sensing of unstained human tissues

Identifying positive surgical margins after resection of cancer often triggers re-excision and adjuvant treatments. Incomplete initial resections result in poorer patient outcomes, psychological and financial stress to the patient and increased healthcare costs. Surgical margins are typically assessed post-operatively using time consuming and expensive slide-based histopathology tissue analysis. Currently, a real-time non-contact virtual histology-like intraoperative margin assessment tool is not available. To address this need, we have developed a non-contact multi-wavelength reflection-mode, photoacoustic remote sensing (PARS) microscope demonstrating chromophore selective contrast in human tissues. We show the capabilities of multi-wavelength PARS microscopy utilizing both 266 nm and 532 nm excitation wavelengths and a 1310 nm detection wavelength. Cell nuclei and hemoglobin were visualized at the cellular scale without the addition of exogenous contrast agents. These works provide a critical step towards a virtual histology tool to provide intraoperative histology-like information in living tissue.

Hepatic resection in children: highlighted and revisited steps

BackgroundHepatectomy in children deserves exhaustive preoperative and intraoperative tools to define the anatomy, minimize blood loss, and confirm adequacy of liver tissue left. The aim of this study is to report our experience in surgical management of liver tumors.ResultsAll liver resections performed in Ain-Shams University Hospital, by the same team, between July 2013 and June 2018 were retrospectively reviewed. Data related to basic demographics, indication for resection, methods of parenchymal resection, blood loss, hospital stay, morbidity, and mortality was collected. The study included 27 patients who underwent different types of hepatectomies. There was a male predominance. Age ranged from 6 months to 13 years. Weight ranged from 5.7 to 33.7 kg. Total operative time ranged from 68 to 322 min, while resection time ranged from 34 to 144 min. Blood loss ranged from 53 to 259 ml. Surgical morbidities included five patients with minor biliary leak, three patients had surgical site infection, and one patient had torsion of the remnant liver necessitating repositioning. Recurrence of the mass was faced in three patients with hepatoblastoma. There were two mortalities; one occurred as a sequela of massive intraoperative bleeding and the other took place due to postoperative hepatic insufficiency.ConclusionFor a safe hepatectomy, thorough familiarity of the hepatic segmental anatomy together with the various techniques for parenchymal resection and vascular control is fundamental. Complications such as biliary leak and torsion of remnant can be easily avoided by simple measures.

Sodium Fluorescein as Intraoperative Visualization Tool During Peripheral Nerve Biopsies

Owing to technical development of specific fluorophore filters, the neurosurgical application of sodium fluorescein (SF) has regained value in brain tumor surgery. The aim of this study was to determine the usefulness of SF during nerve biopsies. This single-center study included 5 cases of nerve biopsies performed under microscope-based fluorescence with SF performed between March 2016 and February 2017. SF was applied intravenously (1 mg/kg body weight). After microsurgical dissection of the involved nerve segment, fluorescence-guided fascicular biopsy was performed. Selection of target fascicles was at the surgeon's discretion and took into account nerve stimulation for preservation of motor function and fluorescence intensity. Correlation to histopathologic examination was examined. Video analysis of intraoperative images comparing target fascicles with intense fluorescent response to adjacent fascicles of the same nerve segment was performed using ImageJ. All patients had motor or sensory deficits. Magnetic resonance imaging findings were similar, depicting long segments of gadolinium enhancement (minimum 11.7 cm). Each biopsy sample was positive resulting in diverse histopathologic results. Digital image analysis revealed a statistically significant difference of the complementary color green (P= 0.0473). Magnetic resonance imaging is the gold standard in diagnostic work-up of peripheral nerve disorders. Longitudinal nerve thickening with positive contrast enhancement is an unspecific magnetic resonance imaging finding. Various pathologies, such as tumors and inflammatory lesions, may cause this morphologic phenomenon. Nerve biopsies may be needed for diagnostic work-up. Intraoperative SF may help to depict the most affected fascicles and identify target fascicles for biopsy and increase diagnostic certainty of nerve biopsies.

Intraoperative Three-dimensional Virtual Reality and Computed Tomographic Guidance in Temporomandibular Joint Arthroplasty of Syndromic Craniofacial Dysostoses

Bony ankylosis of the temporomandibular joints (TMJ) occurs in up to 28% of patients with syndromic mandibular dysostoses. Release of complete osseous ankylosis is particularly challenging due to the lack of tissue planes separating the mandible from the skull base and the presence of congenital skeletal abnormalities. One recent advance in surgical imaging technology is three-dimensional virtual reality (3D VR), now in common use in neurosurgical resections. In this study, we describe the usage of 3D VR in TMJ arthroplasty and compare 3D VR to traditional computed tomographic (CT) guidance. Pediatric patients with syndromic mandibular micrognathia including Treacher Collins, Nager, and cerebrocostomandibular syndrome were retrospectively evaluated between 2008 and 2016. Patient characteristics, complications, inpatient times, and operative times were recorded. Of the 29 children with syndromic mandibular micrognathia treated between 2008 and 2016, 7 were diagnosed with TMJ ankyloses. Four consecutive pediatric patients (mean 8.7 years) undergoing interpositional TMJ arthroplasty with Matthews device placement were retrospectively evaluated. Two patients underwent traditional CT-guided versus 3D VR-guided temporomandibular joint arthroplasty (TMJA). No statistically significant differences were found among the age, complications, or inpatient hospitalization times. The average operative time in the traditional CT guidance group was 300 minute versus 134 minutes in the 3D VR group. Three-dimensional VR is a useful preoperative planning and intraoperative guidance tool. The major difference between VR and older technologies is the improved imaging in 3 dimensions for guidance, thereby potentially decreasing operative times.

A3-A3 Bypass Surgery for Aneurysm: Technical Nuances.

Cerebral bypass remains important for the treatment of complex cerebral aneurysms including dissecting, giant, and fusiform aneurysms not amenable to endovascular treatment or simple clip ligation. For such aneurysms involving the anterior communicating artery complex or its branches, distal anterior cerebral artery (ACA) A3-A3 side-to-side bypass represents a valuable treatment option. Distal ACA in situ anastomosis is recognized to be technically demanding mainly due to the relative depth and narrowness of the interhemispheric surgical corridor and type of anastomosis. To demonstrate technical nuances of A3-A3 side-to-side in situ bypass surgery through case illustrations and operative videos. Elements of the procedure relating to positioning, approach, and anastomosis which have evolved in the operative technique of the senior author were collated based on review of clinical case material, imaging and video recordings of ACA aneurysms treated with side-to-side in situ A3-A3 bypass procedure. Technical elements were contrasted with relevant literature. Nuances relative to patient positioning, selection of craniotomy variants, adjunctive intraoperative tools and microsurgical nuances of the side-to-side bypass procedure are reviewed. Three illustrative operative video cases, along with illustrations, are provided to complement the description of the nuances. In the light of the inherent technical difficulty, as well as the rather limited case volumes, the technical tips provided may contribute to bringing additional refinement and simplicity to the A3-A3 bypass procedure.

Synovial fluid \u03b1-defensin in the diagnosis of periprosthetic joint infection: the lateral flow test is an effective intraoperative detection method

BackgroundSynovial fluid α-defensin is a valuable biomarker for periprosthetic joint infection (PJI). Its diagnostic value for PJI has been widely evaluated recently, but results are inconsistent, especially for different test methods. The objective of this study was to evaluate the diagnostic value of laboratory-based immunoassay and lateral flow testing for the detection of α-defensin against hip and knee PJI.MethodsWe systematically searched MEDLINE and EMBASE for articles on the diagnostic accuracy of α-defensin for PJI published up to September 2018. The pooled sensitivity, specificity, area under the curve (AUC), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were calculated for the evaluation of the diagnostic value of α-defensin for PJI.ResultsNineteen studies were included. Eleven evaluated laboratory-based immunoassay, and 10 evaluated the lateral flow test results. The pooled sensitivity, specificity, AUC, PLR, NLR, and DOR of laboratory-based immunoassays were 0.96 (95% confidence interval [CI] 0.90–0.98), 0.97 (95% CI 0.95–0.99), 0.99 (95% CI 0.98–1.00), 35.0 (95% CI 18.5–66.2), 0.04 (95% CI 0.02–0.11), and 811 (95% CI 220–2990), respectively. The pooled sensitivity, specificity, AUC, PLR, NLR, and DOR of the lateral flow test were 0.86 (95% CI 0.81–0.91), 0.96 (95% CI 0.93–0.98), 0.95 (95% CI 0.93–0.97), 21.2 (95% CI 11.7–38.5), 0.14 (95% CI 0.10–0.21), and 148 (95% CI 64–343), respectively.ConclusionsLaboratory-based immunoassay of α-defensin is highly accurate for the diagnosis of hip and knee PJI. The lateral flow test is less sensitive but still a useful intraoperative detection tool for PJI.

P111. Simulated corrections of cervical deformity using in-construct measures demonstrate that insufficient corrections result in DJK

BACKGROUND CONTEXT Distal junctional kyphosis (DJK) is a major concern following cervical deformity (CD) correction, leading to failed realignment and revision surgery. Undercorrection may be the major factor associated with DJK, however it is difficult to assess because the DJK erodes the correction and worsens traditional measures like cSVA. In-construct measures have been proposed that measure alignment within the fusion separate from the DJK and subjacent compensation. PURPOSE To simulate cervical deformity corrections using surgical planning software to determine if undercorrection results in DJK. STUDY DESIGN/SETTING Retrospective analysis of a prospective, multicenter CD database. PATIENT SAMPLE A total of 69 CD patients. OUTCOME MEASURES Radiographic measures: C2 plumblines, in-construct measures and DJK angle change. METHODS A prospective database of operative CD patients was analyzed for severe DJK (kyphosis change>20° in LIV to LIV-2) and traditional DJK (change>10°). C2LIV-Tilt (angle of a line from the centroid of C2 to the centroid of the lower instrumented vertebra and a line along the posterior vertebral body wall of the LIV) was measured postoperatively and the correction was simulated in the preoperative X-ray to match the C2LIV-Tilt using planning software. Linear regression analysis using C2 pelvic angle (CPA) and Pelvic Tilt (PT) determined the simulated PT to match the virtual CPA. SVA measures were compared in patients with severe and traditional DJK and no DJK. Linear regression analysis was used to determine the C2-T4 and C2-T10 Tilts that correspond to DJK=10° and cSVA=4cm. RESULTS A total of 69 CD patients (mean age 61, 60% female) were included. Severe and traditional DJK occurred in 11 (16%) and 22 (32%) patients; 3 (4%) required DJK revision. Simulated corrections demonstrated that severe and traditional DJK pts had worse alignments compared to no DJK pts: cSVA (42.5 vs 33.0 vs 23.4mm, p .57, p CONCLUSIONS Simulated cervical deformity corrections demonstrated that severe DJK patients have insufficient corrections compared to patients without DJK. In-construct measures assess sagittal alignment within the fusion separate from DJK and subjacent compensation. They can be useful as intraoperative tools to gauge the adequacy of CD correction. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

A study protocol for a randomised controlled trial evaluating the effects of intraoperative computed tomography on the outcomes of zygomatic fractures

BackgroundZygomaticomaxillary complex (ZMC) and zygomatic arch (ZA) fractures are common injuries resulting from facial trauma and frequently require surgical management (Huang et al., Craniomaxillofac Trauma Reconstr 8(4):271-6, 2015). A substantial number of post-operative functional and cosmetic complications can arise from the surgical management of these fractures. These include scarring, inadequate facial profile restoration, facial asymmetries and diplopia (Ellis et al. J Oral Maxillofac Surg 54(4):386-400, 1996; Yang et al. Oral Maxillofac Surg Clin North Am 23(1):31-45, 2011; Kloss et al. Int J Oral Maxillofac Surg 40(1):33-7, 2011). Intuitively, most of these aforementioned complications arise as a result of inadequate fracture reduction; however, current standard practice is to assess reduction post-operatively through plain radiographs or computed tomography (CT) scans. The role of intra-operative CT scanning to assess the reduction of ZMC/ZA fractures and the potential impact on complications, has thus far not been established.MethodsThis is a prospective randomised controlled trial currently being undertaken at the Royal Brisbane and Women’s Hospital. All patients who require operative management of their ZMC or ZA fractures are offered enrollment in the trial. The patients are randomised into two groups: interventional (intra-operative CT) and control (no intra-operative CT). All patients in each group will have post-operative radiographs taken. From these radiographs, the reduction of the ZMC and/or ZA fracture is graded by a blinded assessor. Patients will be reviewed in clinic at 1 week and 6 weeks post-surgery. During these consultations, all patients will be assessed for scarring, diplopia, facial profile restoration and need for revision surgery.DiscussionMany complications associated with surgical management of ZMC and ZA fractures involve poor aesthetic results as a direct consequence of inadequate fracture reduction. Inadequate fracture reduction is predictable given that small incisions are used and only limited visualisation of the fractures is possible during the procedure. This is due to a desire to limit scarring and reduce the risk of damage to vital structures in an aesthetically sensitive region of the body. It follows that an intraoperative adjunctive tool such as a CT scan, which can assist in visualisation of the fractures and the subsequent reduction, could potentially improve reduction and reduce complications.Trial registrationAustralian New Zealand Clinical Trials Registry, ACTRN12616000693426. Registered on 26 May 2016.